Psalm 51:15

The heading of Psalm 51 ties it to the time when Nathan came to David, and the story is told in 2 Samuel 11 and 2 Samuel 12. David took Bathsheba, and to hide what he had done he arranged the death of her husband, Uriah the Hittite. Nathan’s rebuke (2 Samuel 12:1–15) brought him to repentance. Because David was king, his sin was public, and its weight fell on the nation as well as on him, as Nathan’s words in 2 Samuel 12:14 show. Even a king answers to God’s holy law. For a king in that position to confess openly, and then to promise to teach others, was a remarkable act of humility.

The first twelve verses of the psalm are confession and plea. David prays, “Wash me throughly from mine iniquity, and cleanse me from my sin” (Psalm 51:2). He owns that his sin is first of all against God (Psalm 51:4), he asks to be purged with hyssop (Psalm 51:7), and he prays, “Create in me a clean heart, O God; and renew a right spirit within me” (Psalm 51:10). He appeals to God’s mercy alone. With verse 13 the psalm turns outward. Having asked God to renew his spirit and restore his joy, David speaks of what will follow, which is teaching, singing and praise. The psalm then closes with a prayer for Jerusalem and its sacrifices, so a repentance that began in one man’s heart reaches out to all God’s people.

“Then will I teach transgressors thy ways” is a promise made in the expectation of mercy. “Then” looks back to the cleansing and renewal David has just asked for, and once God has restored him, his first resolve is to pass on what he has learned. The Hebrew verb, alammedah, is cohortative, the form a speaker uses for his own firm resolve, so the line carries the sense “I am determined to teach”.

The root of that verb is lâmad. Strong’s gives its proper sense as “to goad”, and in use it means “to learn” in its simple form and “to teach, instruct, train” in the form used here, which is to cause someone else to learn. David means instruction that changes the way people live, covering the practical, everyday side of walking with God as well as the truth about him.

His pupils are “transgressors”. The word comes from pâshaʻ, which means to break away, to rebel or revolt against authority, and here the authority is God and his covenant. It describes a deliberate breaking of the bounds God has set. David had been exactly that kind of man, so he speaks to rebels as one who has stood among them, with a compassion born of his own fall.

What he teaches is “thy ways”. The word derek is a road or path, literally one that has been trodden, and from that it comes to mean a course of life or a way of acting. God’s ways are his righteous requirements and statutes, his character, and the way he deals with people, including the forgiveness David has just received. The Psalms set God’s way against another one: “For the LORD knoweth the way of the righteous: but the way of the ungodly shall perish” (Psalm 1:6). Isaiah foresees many people going up to the mountain of the LORD and saying, “he will teach us of his ways, and we will walk in his paths” (Isaiah 2:3).

The second half of the verse gives the outcome David hopes for. “Sinners” are chatta’im, people who miss the mark and fall short of God’s standard. It is a broader word than “transgressors”, though the two overlap, and the two halves of the verse match each other. The transgressors are the sinners, and being taught God’s ways leads to turning back to him.

“Converted” translates shûwb, to turn back or return. The verb can be used of things that pass or subside, such as anger turning away (Genesis 27:44). Here it is used of people, and it has a direction, “unto thee”. Sinners leave the wrong road and come back to God himself, with a change of heart and life. Peter preached the same call in Jerusalem: “Repent ye therefore, and be converted, that your sins may be blotted out” (Acts 3:19).

David does the teaching, and the turning is God’s work in the hearts of those he teaches. God promised through Jeremiah, “I will give them an heart to know me, that I am the LORD: and they shall be my people, and I will be their God: for they shall return unto me with their whole heart” (Jeremiah 24:7). God uses human teachers, and he himself gives the heart that returns. That keeps anyone who teaches his ways both diligent and dependent on him.

The pattern runs on into the New Testament. Jesus sent his disciples to “teach all nations” and to teach them “to observe all things whatsoever I have commanded you” (Matthew 28:19–20). Paul says that God, who has reconciled us to himself through Christ, has given us the ministry of reconciliation, so that we are ambassadors for Christ, pleading with people to be reconciled to God (2 Corinthians 5:18–20). Those who have received mercy are the ones God sends to offer it.

Bloodguiltiness is the guilt of having shed innocent blood, and David means the blood of Uriah, whose death he arranged. The Hebrew word is dâm, “blood”, as that which causes death when it is shed. Especially in the plural it is used for bloodshed and for the guilt that comes with it, and the KJV’s “bloodguiltiness” gives that sense. In Israel the shedding of innocent blood was among the gravest of all offences. It wronged the victim, it was a sin against God, and the law says that blood defiles the land itself (Numbers 35:33–34). The guilt carried legal, moral and spiritual weight together.

After praying to be washed within (Psalm 51:2, 51:10), David now names the most terrible thing he did. This is the most specific plea in the whole psalm, and naming it plainly is part of his repentance. He takes the full weight of what he has done and brings it to God by name.

“Deliver” is nâtsal, to snatch away, to rescue someone out of danger. With this verb the person rescued is the object, as in “deliver them out of the hand of the Egyptians” (Exodus 3:8), and the danger is marked by “from” or “out of the hand of”. So David is the one to be rescued, and the danger he asks to be pulled out of is his own guilt.

The vow that follows is to be spoken by David’s tongue, lâshôwn, the word for the tongue itself and for language. The tongue stands for his speech, now given over to praise. “Sing aloud” is rânan, to give a ringing cry or shout, usually for joy. The word is often used of praise that people resolve on or are called to (“let us sing”), and David resolves it here as a vow. It is loud and public praise, the opposite of a private whisper.

His theme is righteousness, tsᵉdâqâh, which means rightness, justice and virtue. He will sing of God’s righteousness, and the whole point is that it belongs to God. A man asking for mercy might be expected to sing of mercy, and the answer is that God’s righteousness includes his faithfulness to his covenant and his way of forgiving a sinner while remaining true to his own holy character. John says the same: “If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness” (1 John 1:9). Paul shows how this holds together in Christ, in whom God sets forth his righteousness, “that he might be just, and the justifier of him which believeth in Jesus” (Romans 3:21–26).

Forgiveness turns David’s voice, which shame could have silenced, into an instrument of praise. He knew this joy well: “Blessed is he whose transgression is forgiven, whose sin is covered” (Psalm 32:1–2). God’s own invitation is, “though your sins be as scarlet, they shall be as white as snow” (Isaiah 1:18). And praise that springs from rescue is a theme of David’s elsewhere: “I will bless the LORD at all times: his praise shall continually be in my mouth” (Psalm 34:1–3).

“O Lord, open thou my lips” uses the title ʼĂdônây, “Lord”, which honours God as sovereign master, able to act on David’s condition. The verb pâthach means to open wide, to loosen or to set free. The word for lips, sâphâh, is the lip itself, and by extension speech and language, and it is also used of the edge, brim or shore of a thing. Here “lips” stands for David’s whole power of speech in worship.

David could still talk. What his guilt had shut was his praise. Sin had broken his fellowship with God, and with it his freedom to worship from the heart. He describes the same experience in another psalm, where keeping silent about his sin wore him down until he confessed it: “I acknowledged my sin unto thee, and mine iniquity have I not hid... and thou forgavest the iniquity of my sin” (Psalm 32:3–5). So he asks God to open what only God can open. True praise is God’s gift, flowing from a heart that God has cleansed and set free.

Isaiah’s call shows the same order. Isaiah cried, “Woe is me! for I am undone; because I am a man of unclean lips”, and a live coal from the altar touched his mouth, his iniquity was taken away, and then he was sent (Isaiah 6:5–7). God cleanses the lips first, and then they speak for him.

Every part of these verses finds its fullness in Jesus. The ways of God that David vowed to teach are perfectly revealed in Christ, who said, “I am the way, the truth, and the life” (John 14:6). He came “not to call the righteous, but sinners to repentance” (Mark 2:17), and the turning back to God that David longed to see is the new birth the Holy Spirit gives through faith in him (John 3:3–8).

David’s plea about bloodguilt meets its answer at the cross. The Lamb of God takes away the sin of the world (John 1:29), and his innocent blood was shed for the sins of others. The sacrifices of the law taught that “without shedding of blood is no remission” (Hebrews 9:22), and they pointed to his one sufficient sacrifice. God “hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him” (2 Corinthians 5:21). So when believers sing aloud of God’s righteousness, they sing of the righteousness he has given them in his Son.

Christ also opens the lips. Through his blood we have “boldness to enter into the holiest” by “a new and living way” (Hebrews 10:19–22), and as a holy priesthood we offer spiritual sacrifices acceptable to God by Jesus Christ (1 Peter 2:5), the “sacrifice of praise” (Hebrews 13:15). Heaven itself rings with a new song to the Lamb: “thou wast slain, and hast redeemed us to God by thy blood” (Revelation 5:9–10). And the risen Christ who sends his people to teach all nations (Matthew 28:19–20) turns David’s vow into the lasting work of his church.

These verses show what God’s forgiveness does in a person. It reaches the worst thing we have done, the sin we can hardly bring ourselves to name, and David names it before the God of his salvation. It gives back a joy that sings. And it sends the forgiven out with a message, because those who know God’s ways from the inside, the way of mercy for rebels, are the very people he uses to teach them.

So you can bring your gravest sin to God by name, as David did, and ask him to deliver you from it. You can ask him to open your lips when guilt or coldness has shut them, and he delights to answer that prayer. And whatever you have been forgiven can become the story you tell, so that others hear of God’s righteousness and turn back to him.