A Cry For A Clean Heart: Sermon on Psalm 51

Below is a sermon I preached at Symons Valley Community Church on July 29. It was one of the congregation's favorites (by me, anyway).
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I love the Psalms. They express the heart of God’s people. all the joy, all the sorrow, all the rage, all the love, all the anger, all the frustration, all the hope of a walk with God in a fallen world is on full display.
The Psalms are in a class by themselves as Scripture. While being God’s inspired and perfect words for us, they are also the words of men to God. Moved by the Holy Spirit, real believers facing real trials and struggles poured their hearts out to God in song and prayer. And this has given us a priceless treasure - an inspired hymnbook, full of inspiration and wisdom.
What makes them so edifying to us, I think, is the sheer variety we see in the Psalms. There are songs of praise. There are songs of thanksgiving. Cries for help and cries of joy. Words of anger and words of comfort.
Our text today is a song of confession and lament. Psalm 51. It is a well-known passage, and expresses better than perhaps any other writing the response of a believing heart to one’s own sin and wickedness.

CONTEXT
It must have been a hot day. It was in the spring, when, as 2 Samuel 11 puts it, “the kings go out to battle.” The beginning of the campaign season, when the rains have stopped and the roads can handle the heavy traffic that goes along with an army on the move. It was probably April or May, and in Jerusalem, that’s a warm time of year. Jerusalem is on a hilltop not far from the Mediterranean Sea, and not far from the desert, either. The climate would have been something like California.
And in an age without air conditioning, as Erin and I found out by experience last week, staying indoors is an ordeal to be avoided. I don’t blame David for going out on the roof, then. He was probably trying to get out of the stuffy halls of the palace and catch a nice breeze.
A twist of fate - well, in God’s world, there are no coincidences. Samuel tells us that Bathsheba was having a bath on the rooftop. And, as it happened, she was doing this at the same time David took his walk on the roof. By God’s plan, these two wound up on their rooftops at the same time. This was a test.
And think about who was being tested here. David was a man after God’s own heart. He was a firm believer in God, a faithful worshipper and servant. He was a prophet in his own right, who wrote dozens of Psalms we still read and sing today. Throughout the Bible, he is spoken of in glowing terms - a king held up as a model to be imitated, an example of living faith.
And yet David fails the test. He could have averted his eyes. He could have gone right back inside, found something else to busy himself. There was a war on, after all - maybe he could have gone over some of the messages from the front, or grabbed a horse and travelled up there himself.
The Bible reminds us that all sin is our own responsibility. God himself tempts no one, though he allows us to face temptation from others. And in every time of temptation, God ensures that we will face no more than we are able to bear. In fact, he gives us a way out. And like I said, David had a way out.
What a devastating fall. An astounding display of sin. We have lust. Covetousness. Adultery. Deception - trying to have Uriah think the child is his, remember? Betrayal. Murder. And so this psalm, even before we get into the text itself, has a vital lesson for us all in its historical context. David was one of the greatest heroes of the Bible, and he failed.Badly. His status as a prophet of God didn’t protect him. His character as a kind and generous man didn’t keep him safe. Within David’s heart was wickedness - the same evil nature that all of us still fight against in our daily walk. If David, of all people, could fall - despite his character, his knowledge, his wisdom, his grasp of the things of God - so could any of us. And not just into any sin - into adultery and murder. Some of the most shocking sins imaginable.
There’s our first lesson. If David could fall, so can we. If he were capable of such sin, so are we. Let us be warned.
Now, the psalm itself. As you read it, you can feel David’s anguish. He is a broken man. He has looked into his heart and examined his ways, and he is disgusted with himself.
There’s three things we can learn from Psalm 51 – three things that we need to hear and apply in our own lives. First, David has some important insights into his own sinfulness. Second, David cries out to God to change his heart. And third, the way David prays – how he approaches God and what he says – is a good example for us to follow.

WHY DAVID WAS PRAYING
First, David talks about his sin. His words about himself should not be taken as exaggeration or hyperbole. David has some valuable insights into sin that we need to recognize. Let’s start at verse 4:
“Against you, you only, have I sinned, and done what is evil in your sight.” That sounds a little odd, doesn’t it? Against God? God only?
Think for a moment. Just how many people did this sin affect? David was a married man, for starters. What about his wives? By this point, he had at least two - Michal, Saul’s daughter, Abigail, Nabal’s widow, and probably others. David surely sinned against them - breaking the covenant vows he had made to them to be their husband!
What about Uriah? Not only did David take his wife, he betrayed him, deceived him, and killed him.
How about Bathsheba? Whether she has some responsibility in this situation or not, the fact remains that David, like so many men today, looked on her and lusted after her. He treated her like a piece of meat, a means of pleasure. What about her?
What about David’s children? Their father - treating their mothers and his own family with such carelessness and disrespect?
The people of Israel? Their king has dishonoured himself and by extension the entire kingdom. How can David say that he had sinned against God alone?
Because all the people I just listed belong to God. A sin against them is fundamentally a sin against their Creator and Master.
Even more than that, though, is the nature of sin itself. Sin - what is it? It is a failure to meet the standard of God. It is missing the mark. Falling short of God’s expectations.
And so every sin is against God. He is the final Judge. The buck stops with Him. There is no court of appeal. Every single sin ever committed is ultimately and finally dealt with by God, and God alone. Every sin is ultimately and finally against God - and God will require an account for it. Don’t forget that.
That’s the first point about sin - it’s against God and God alone. We can’t blame God for it. There will be no room for excuses - even though God is sovereign, even though your actions are all a part of His plan, it is you who commits them. It is you who forms the desire in your heart - not God. It is you who gives in to temptation - not God pushing you into it. Like David said, “you are justified when you speak, and blameless when you judge.” Our sin is our own, and God will have nothing to do with it. His judgment is just.
Let’s read on: “Behold, I was brought forth in iniquity, and in sin did my mother conceive me.”
Is this exaggeration? David elsewhere speaks very highly of his mother. He was the youngest in his family - his mother and father were married. There was no sin in the way he was concieved.
What David is saying, then, is this. He was sinful from birth. This isn’t poetic exaggeration. Human beings are sinful by their very nature. Erin and I saw a little girl of only two or three years old on Friday, ripping a toy out of Caden’s hands at the photographer’s, screaming “No! It’s mine!!” Caden will have fits of rage if you try to take a remote control or set of keys out of his hands.
Sin is not a learned behavior, like talking or potty training. It’s innate and natural, like eating and breathing. We are not sinful because we sin - rather, we sin because we are sinful. The reason every single human being sins and is guilty in God’s eyes, no matter what culture they live in or life situation or upbringing they come from, is because their sinfulness is part of their very nature. Yes, from birth - from conception. And while a very young child, especially in the womb, may not be physically able to commit acts of sin, and while their actions may not be willfully sinful, their basic inclinations are still sinful. Their nature is sinful.
This is an uncomfortable teaching, because it feels wrong. Babies are cute - I know! I know it well! They’re beautiful. But they are also corrupt - born into spiritual slavery. Stillborn with respect to spiritual things. Children don’t grow up naturally generous and giving - these things have to be modeled and taught and enforced. They have to overcome a naturally selfish nature.
And it’s important for us to realize this - vital that we get this. If you don’t get sin right, you can’t get the Gospel right. And if you don’t get the Gospel right, there can be no salvation.
Listen - Jesus didn’t come to maximize some kind of natural human potential, like so many today believe. That’s a false gospel - it’s a lie. The only natural potential in mankind is toward greater and greater evil. No, Jesus came to SAVE us. From what? From sin - from OURSELVES! From what we bring upon ourselves - the punishment and wrath of an outraged and offended God.
That’s the second point about sin - sin is natural to human beings.
And sin must be dealt with. David cries out for God to purge him with hyssop. To purify him with hyssop. What does this mean? In ancient Israel, the Law of Moses prescribed certain rituals be performed for certain problems. David is referring to one of these - the rite of purification for leprosy. He’s comparing sin to leprosy.
In our age, a simple medication can stop the disease (though reversing its effects is a lot harder). In ancient Israel, if a person had recovered from leprosy, the victim was to go to the priest, who would perform this ritual, which I am reading from Leviticus 14: 2-7.
So not only does David compare his sin to leprosy, but he compares the purification from sin to that from leprosy. There’s a lot in common. An animal is sacrificed - a bird is killed - just as Christ had to die as punishment for our sins. The bird’s blood is sprinkled on the leper, just as Christ’s blood washes us clean. The ritual takes place over running water, a Biblical symbol of the water of life that flows from Christ in the form of His Holy Spirit.
David is crying for God to purify Him, to remove the guilt and the stain of his sin. That’s the third point about sin - it must be removed and cleansed by blood. This is what the Father did for us, sending His Son to shed His blood for our sin.

WHAT DAVID WAS PRAYING FOR
But not only must salvation be purchased by Christ on the cross - it has to be applied to the individual believer in his own life. The ritual we just talked about didn’t end with the death of the bird – its blood had to be sprinkled on the leper, applied to the leper. The work of Christ is followed by the work of the Spirit. It’s not enough that sin be paid for - the whole purpose of salvation is not just to rescue sinners from hell, but to restore them to the service of God’s glory.
David realized this. He dredged the depths of his own heart and brought up filth and evil. He was shocked and appalled at what he turned out to be capable of. Horrified and guilt-stricken, he turned to God in prayer, and asked - asked for what?
For help in doing better? No.For better luck next time? No.
No, David recognized the root of the problem. He saw the source of the evil in his life in his lyin’, cheatin’ heart. He didn’t adopt the twenty-first century attitude - that given the right conditions, the right encouragement, and enough self-esteem, that the good in him would triumph. David knew that there was no good in the heart of man, except for God’s grace.
And so he prayed for the only thing that would help - he prayed for a clean heart.
What I want to draw your attention to is the parallel between his appeal for a clean heart in verses 10-12, and his description of the heart the God desires in verse 17. There, David rules out the idea that sacrifices and rituals can cover sin or cause God to accept a sinner. What kind of sacrifice will God accept? A broken spirit; a broken and contrite heart, he says.
Is he talking about two different things? Is he saying that he is approaching God with a broken and contrite heart, so that God will give him a clean heart? Well, David is certainly broken. He’s contrite – that means repentant and ashamed. But I don’t think these are two different things. David is ashamed and disgusted by the state of his heart right now – otherwise, he wouldn’t be asking for a clean one!
No, David is confessing that what God requires – a broken and contrite heart – is something he does not have. How horrible he must have felt here! Not only has his own heart, his own nature, betrayed him and thrown him into the depths of sin – he’s also realized that, as guilty and broken as he feels about that sin, it’s still only the guilt and shame and sorrow of a sinful and wicked heart. It’s not enough! A broken and contrite heart God will not despise – but my heart isn’t that! My heart led me into sin! My shame and my guilt are not enough!
As Paul said, “Who will deliver me from this body of sin and death?”
That’s why he cries out for mercy at the very beginning – he can’t earn God’s favor. All he can do is plead for God’s grace, in hopes that God will Himself make David acceptable in His eyes. That’s the essence of Christian salvation – and it’s the essence of the Christian life after the point of salvation, too. David recognizes that a willing spirit, one that desires to follow God, one that would be acceptable to God, is something only God can give him – “uphold me with a willing spirit.”
And there is hope. Yes, David knows his heart is unacceptable. But he is broken nonetheless. Not broken enough, maybe, not nearly as remorseful as he knows he should be. But there is shame and remorse, brokenness and guilt. These are signs that God is already beginning the process of reconciliation. If it is true that it is not I that does these things, but God working in me, that applies to guilt and shame as well.
Every one of us has screwed up, time and again. And when we do, it has consequences. We begin to doubt our own salvation – David says here, “Cast me not away… Take not your Holy Spirit.” When we fall into sin, God often will pull back from us a little, cause us to doubt and to search for Him again. God wants us in a position where we realize constantly that we need His grace to go on – that we simply can’t do it on our own.
There are Christians who believe that a sinless life is possible on this side of death. There is much truth in what they are saying – we all have the Holy Spirit, and God always gives us a way out. Sin is something that as believers we have power over – we don’t have to sin. But the Bible is quite clear that even Christians will continue to struggle with sin until death. The Apostle John wrote that “if anyone says he has no sin, he is a liar and the truth is not in him.”
This is not an excuse for accepting sin as inevitable, though. Rather, we should look at that truth as a motivation to keep crying out to God, as David did, that He might give us clean hearts, that he might uphold us with a willing spirit. We must never grow complacent – we must always be stretching our arms out to God and pleading with Him for grace.
That’s the second message this passage has for us. We need God to create in us clean hearts. We need Him to uphold us with a willing spirit – to keep us on the straight and narrow by His strength. We can’t do it on our own!

HOW DAVID PRAYED FOR IT
Finally, we could all use a reminder of how God is to be approached after sin. Psalm 51 is possibly the best advice anyone could offer to a Christian grappling with his relationship with God after sin. Is anyone struggling with their walk with God? Does anyone lack joy and wish for God to restore it unto them? If anyone here has sinned and wishes to restore their fellowship with God, this passage is for you. How does a Christian who has drifted from God restore that relationship? What should we ask for? Let’s walk through the psalm and point out a few valuable lessons.
First, notice how David begins his prayer. “Have mercy upon me, O God, according to your lovingkindness.” This is the Biblical sinner’s prayer – a heartfelt cry for mercy. We think of Jesus’ parable of the tax collector and the Pharisee in the synagogue, where the tax collector prays by saying, “Lord, have mercy on me, a sinner!”
David pleads for mercy because he knows he deserves punishment. It’s an act of humility. We would do well to remember that in our own prayers. Every breath we take is a gift from God’s hand, and when we sin, the only hope we have is God’s mercy. A humble reliance on that mercy is what we call faith. So that’s the first practical point – beg God for mercy. He is merciful and compassionate!
Next, he confesses his sinfulness. Not only does he confess the specific sin – he mentions bloodguiltiness in verse 14 – but he confesses and takes responsibility for his sinful condition. For his sinful nature. That nature belongs to all of us. It’s ours. And it is our responsibility to deal with it, in the power God provides. Confessing our sins and our sinfulness humbles us before God, because it reminds us that He is pure and perfect and that we do not meet that standard – that we need His help. That’s the second step – confess your sins!
Third, he asks to be purified – to be washed clean. For the Christian, forgiveness of sins is not enough. No – it’s not enough! Not only do we need forgiveness from sin, but we need freedom from it. Whenever the Bible talks about freedom, it means freedom from evil and sin. God has saved us for a purpose – to raise up a people for His own possession who are zealous for good works! Mere forgiveness would get us out of hell, but it won’t enable us to serve God or to live a life that glorifies him.
Forgiveness from sin is one thing – cleansing from it and the power to resist it are another. We need both, and we need to constantly ask God for both. We need to ask God to purify us from our sins.
Fourth, he does not complain about the consequences of his sin. David paid dearly for his sin. On top of losing a friend and a solid warrior in Uriah, he was publicly humiliated by the prophet Nathan. Worst of all, his infant son died after only seven days, just as God had promised.
David paid dearly for his sin. Did he object? Not in the least. He admitted that God was righteous in his judgment in verse 4. God was in the right, he said. Even more, in verse 8 he asked God that the bones that had been broken would rejoice – in other words, that David might be given strength and wisdom to rejoice in the discipline he had received! When God sends consequences our way, we drop to our knees, we confess that God is right in His judgment, and ask that we may come to accept and rejoice in the discipline that points us back to Him. We don’t complain – we rejoice in God’s discipline.
We’ve already looked at David’s request for a clean heart – one not only free from sin, but one that is as broken and contrite as God requires. Why does David ask this? For himself? Actually, no. The reason David gives for his prayers and requests is not self-centred. It’s God-centred. We would do well to pay attention here. Why does David ask for a clean heart, for a renewed spirit? Verse 13 – then I will teach sinners your ways, and they will be converted to you.” Verse 14 and 15 – that I might declare your righteousness and sing your praise. Why is David asking for a clean heart? That through him, God may be glorified! Do you want to teach sinners God’s ways? Do you want to see unbelievers come to faith?
Do you want your praise and worship to be meaningful and edifying? You need a clean heart and a right spirit. Cry out to God for it! Ask Him for it for His sake, not yours! Pray in His name – not yours! Even a prayer for restoration and forgiveness like this is done for God’s glory – like everything should be!
And finally, look to verse 18. David prays for Zion – that’s Jerusalem – that God might be good to them. David did not forget what we all to often fail to remember, and that’s this: Our sin has consequences not just for us, but for others as well. Our sin affects not just our own spiritual selves, but the spiritual walks of those around us. When our foolishness and selfishness brings calamity down, it often causes collateral damage. God warned His people that the punishment for sin would follow them down to the third and fourth generation. Don’t ever forget this, especially within the context of the church, and those who have wives and husbands and children. When we approach God to ask for forgiveness and restoration, we cannot forget those who have been affected by our sin.

CONCLUSION
We stumble and we fall. As long as we have sin in our hearts, as long as we live in this fallen world, we will struggle with temptation and sin, and sometimes we may lose the fight. And when that happens, our relationship with our Heavenly Father suffers. God grows more distant as the Holy Spirit is grieved. Psalm 51 teaches us that restoration and reconciliation are necessary – and that, for the one who cries for mercy out of faith in God, it is a sure hope.
Sitting here this morning, it might be you who has sinned and needs that restoration. Or you may be like the city of Zion, whose pain and suffering David also prayed for. Maybe you’re one of those harmed by the selfishness and thoughtlessness of another. And that sin committed by another has you struggling with your own relationship with God. You have the same hope! The same God who not only waits to hear your prayer, but moves to make your prayer possible in the first place! Who begins the process of healing and restoration before you even think to ask – for how could we ask at all, without the grace of God working through us? Perhaps you do not have because you do not ask. With God, all things are possible. Cry out to Him!
Don’t ever despair. David saw the worst of what man can do, and it came straight from the depths of his own heart. But God, who is faithful – remember, it depends on God – drew him out of the depths and restored him. If David could be restored after such a fall, then nothing you have done is beyond the healing power of God. Cry out to him! Cry for mercy!