Psalm 51 is a penitential psalm in which the psalmist confesses his sin to the Lord and seeks God’s mercy and forgiveness. You’ll see from the title that the background to the psalm is the time when Nathan the prophet confronted David about his sin with Bathsheba. David had committed adultery with Bathsheba; and then, when she became pregnant, he arranged for her husband, Uriah the Hittite, to be killed on the battle field. You can read the story in 2 Samuel 11 and 12 where it tells us how Nathan went to David and told him the story of the rich man who had plenty of sheep and cattle of his own; but when a guest came to stay at his house, the rich man took a poor man’s only lamb and gave it to his guest for food. When David heard the story, he burned with anger against the rich man. ‘He deserves to die’, David said. And do you remember? Nathan said to David: ‘You are the man.’ You are the man, because you’re the rich man who took away Uriah’s wife. In fact, he not only took Uriah’s wife, but he took Uriah’s life. And David took to heart what Nathan had said and afterwards he wrote this psalm in which he confesses his sin and prays for God’s mercy.
Verses 1 to 2
In the first two verses, he uses three terms for sin. We’ve come across these words before in Psalm 32 which is another penitential psalm.
The first term is translated ‘transgressions’ by the NIV, but it can also be translated as ‘trespasses’. Just as a trespasser sees the ‘no entry’ sign and disregards it and keeps going, so the transgressor sees God’s ‘no entry’ sign and disregards it and keeps going. God in his law says to us: ‘You shall not do this.’ But what do we do? Well, so often we disregard what he has said and we keep going.
The second term is ‘iniquity’. This word can mean ‘to go astray’, but it often refers to our guilt.
And the third term is ‘sin’ and this is almost the opposite of transgressions. The person who transgresses God’s law does what God has forbidden. However, when David refers to his sin, he’s referring to the way we fall short of doing what God requires. When we transgress God’s law, we do what’s wrong. When we sin against God’s law, we fail to do what’s right. So God in his law says to us: Do this. For instance: Love the Lord with all your heart. Love your neighbour as yourself.
But instead of doing what God requires, we fall short.
So, David refers to his sins in this threefold way: doing what God has forbidden; falling short of what God requires; the guilt which arises because of our sin. He knows that he’s a guilty sinner who has done what’s wrong and who has failed to do what’s right. And now he appeals to the Lord for mercy and for forgiveness. And he uses three terms for forgiveness.
Firstly, he asks the Lord to blot out his transgressions. He wants the Lord to wipe them out and even to scrape them off and to remove them. Think of the way a teacher wipes the board clean at the end of the day so that whatever was written on it is removed completely.
Secondly, he asks the Lord to wash away all his iniquity. We’re now to think of someone washing clothes thoroughly to remove every last bit of dirt and every single stain. Because we’re sinners, we’ve guilty before the Lord. And so, the psalmist asks the Lord to wash away his guilt.
And thirdly, he asks the Lord to cleanse him from his sin. This is a word which comes up a lot in the book of Leviticus to refer to the things people had to do to purify themselves so they could enter the tabernacle and worship the Lord. But the psalmist is not thinking here of ceremonial uncleanness; he’s thinking of moral uncleanness and how he wants to be washed and cleansed from all his sin which would keep him from the Lord.
So, there are three terms for sin and there are three terms for forgiveness. And notice that he bases his appeal for mercy and forgiveness on the character of God. So, he refers to God’s unfailing love, which is his covenant love for his people and includes his faithfulness to them. And he refers to God’s great compassion, which is his kindness to those who are helpless.
So, why should the Lord forgive David? It’s not because David deserves to be forgiven. David deserves to be punished for his sin, doesn’t he? So, he bases his appeal on God’s character: because you’re a God of unfailing love and because you’re a God of great compassion, have mercy on me and forgive me. If God’s love was not unfailing, and if he was not compassionate, there would be no hope for David; and there would be no hope for you, because you too are a guilt sinner who does what is wrong and who fails to do what is right and you deserve to be condemned and punished forever. But the good news is that the Lord is all of these things and more besides and he promises to have mercy and to forgive all who come to him humbly, confessing their guilt and shame.
Verses 3 and 4
But let’s move on to verses 3 and 4 where David confesses his sin. He says that he knows his transgressions and his sin is always before him. So, instead of hiding his sin, or pushing it out of his thoughts, he’s acknowledging it and he’s owning up to it.
Our church’s Shorter Catechism helps us to understand verse 4. ‘What is sin?’ the Catechism asks. And the answer is that sin is any failure to measure up to what God requires or any disobedience to his commands. In other words, sin is always in relation to God, because it concerns his laws and his commands. So, David sinned against Uriah and Bathsheba when he slept with Bathsheba and when he arranged for Uriah to be killed. He sinned against them. But sin is ultimately against God, because by sinning, we’re doing what he forbids or we are not doing what he commands. So, David confesses his sin and he acknowledges that God would be right to condemn him.
Verses 5 and 6
And he goes on in verses 5 and 6 to say that he’s always been a sinner. So, he was sinful at birth. In fact, he was sinful from the moment of his conception. You see, the reason we’re sinners is not because we sin and do wrong. No, the reason we sin and do wrong is because we’re sinners. We’re sinners by birth, or by nature. That’s what we all are. We’re all sinners by nature and therefore sinning against the Lord and doing what is evil in his sight comes naturally to us.
Verse 6 is difficult to interpret, but he seems to be saying that God desires truth and wisdom to be in our inner being. However, because we’re sinners by birth, such truth and wisdom is missing from us. So, think how devious David was, when he tried to cover up his adultery; and instead of doing what is wise and good, he did what is foolish and wrong.
Verses 7 to 12
In verses 7 to 12 he’s asking the Lord for forgiveness and renewal. So, first of all, he asks to be cleansed with hyssop. A branch from a hyssop bush was used to paint blood on the doors at the time of the Exodus. But in Leviticus, the priest was commanded to use hyssop to sprinkle blood for cleansing. So, David is using this imagery to ask the Lord for forgiveness. And he wants the stain of his sin to be washed away and for all trace of his guilt to be removed, so that he will be whiter and cleaner and purer then even snow.
And before he confessed his sin, he was miserable. And he refers in verse 8 to crushed bones to convey to us how his guilt weighed down on him. And we do feel weighed down by guilt, don’t we? And we feel miserable when we’ve done wrong. We have no peace, because we know we’re guilty before God. There may be others around us who are full of joy and gladness, but we can’t experience what they’re experiencing. And perhaps we come to church, and while the rest of the congregation is praising God with joy, we’re don’t feel any joy, because our conscience is accusing us. Well, David prays to the Lord to let him hear joy and gladness again and let his crushed bones rejoice. And that will only happen when he is assured of God’s forgiveness: when the Lord hides, or turns, his face from his sins, so that he no longer pays attention to them, but forgets them; and when the Lord blots out his iniquity so that all record of them is gone. So, he’s asking for forgiveness.
But then, he also asks for renewal, doesn’t he? He wants a pure heart and a steadfast spirit. That is, he wants a spirit that is steadfast in obeying the Lord. So, he doesn’t want to disobey the Lord again and he asks the Lord to work in his heart to enable him to do God’s will and to obey his commands. And in verse 12 he asks the Lord for a willing spirit. A willing spirit is probably the same as a steadfast spirit. So, he’s asking the Lord to renew him inwardly and to make him more and more willing to do God’s will.
So, he’s asking the Lord for forgiveness and renewal. He wants the Lord to pardon him and he wants the Lord to renew him so that he will not sin, but will obey the Lord and do his will.
Before moving on, let me try to explain verse 11 where he asks the Lord not to take his Spirit from him. In the New Testament, we’re taught God is with us always by his Spirit. When the Spirit comes to us, he doesn’t come and go, but he dwells in us permanently and is the deposit, guaranteeing our inheritance. So, though we sin, and may grieve the Holy Spirit, God will never take his Spirit from his people and he will never remove our salvation.
However, in Old Testament times, God would send his Spirit on some of his people to enable them to serve him in a special way. So, he sent his Spirit on Samson to give him the strength he needed to defeat the Philistines. And he sent his Spirit on Saul to enable him to serve as king of God’s people. But when Saul proved unfaithful and disobedient, God took his Spirit from Saul. Well, now that David has sinned against the Lord, he pleads with the Lord not to do to him what he did to Saul.
And here’s the thing: letting his Spirit remain, and letting David continue as king, is the evidence that God had indeed pardoned him. So, his request in verse 11 is once again related to his desire for complete forgiveness. He’s saying: I know I don’t deserve to remain as your king, but have mercy on me and forgive me for my sins and let me continue to serve you in this way. And whenever we fall into serious sin, we’re overwhelmed with guilt and shame and very often we feel we can no longer serve the Lord in his church. But the Lord was willing to pardon David, so that he continued to serve him as his king. And in the New Testament, after Peter denied knowing the Lord, the Lord forgave him and appointed him to be an apostle. When the Lord forgives his people, he really does forgive us and he does not hold our sins against us.
Verses 13 to 19
My time is up. But let me just say briefly that David vows in verse 13 to teach transgressors God’s ways. If God forgives him, he will tell others about God’s willingness to pardon sinners so that they too will be encouraged to turn to the Lord for forgiveness. And as one of the commentators points out, David has been teaching countless numbers of people down through the generations by means of this psalm. And he promises that he will sing of God’s righteousness and he will declare God’s praises. I have a colleague who was once asked why the members of his church sang enthusiastically whereas the singing in other churches was so poor. Can he explain it? Well, he said it’s got nothing to do with the choice of songs or with the instruments. He said that in his experience people will sing enthusiastically when they’ve got something to sing about. And when people know the depth of their sin and the greatness of God’s forgiving grace, they will sing with all their heart.
What is God looking for in his people? A broken spirit and contrite heart. In other words, he’s not looking for people who boast about their good deeds; but he’s looking for people who weep over their sins, because those who weep over their sins will rejoice in his salvation.
And God is able to forgive us, because of Christ our Saviour, who came into the world as one of us and who gave up his life in our place to pay for our sins in full. He was pierced for our transgressions and he was crushed for our iniquities; the punishment that brought us peace with God was upon him; and by his wounds we are healed. We’re the ones who go astray and who fall short, and who do wrong; and each of us has turned to our own way, because we’re sinners by nature. But the Lord our God laid on Jesus Christ the iniquity of us all.