We return now to psalms attributed to David, with Psalm 51 being the first in Book II of the Psalter that bears his name. We read this psalm earlier in conjunction with the event described in the superscription—that of the prophet Nathan confronting David after his sin of adultery and murder (see the Beyond Today Bible Commentary on 2 Samuel 11 as well as 2 Samuel 12:1-13; Psalm 51; 2 Samuel 12:13-31; 1 Chronicles 20:1-3). David immediately confesses, "I have sinned against the LORD" (2 Samuel 12:9, 13). And here in his psalm of repentance, David provides a model of repentant prayer for all of God's people when they sin. It may have been placed here in the Psalter as a response to the calling to account and instruction on sacrifices God gives in Psalm 50.

In Psalm 51, David doesn't justify his actions or try to improve his position. He appeals to God for mercy, hesed—God's unfailing, steadfast love (verse 1). David agonizingly faces what he has done and confesses it to God using all the basic Hebrew words for sin. The word "transgressions" (verse 1) is from the Hebrew pesha, meaning transgression in the sense of rebellion or revolt. "Iniquity" in verse 2 is from awon, meaning perversity, wickedness or fault. The word for "evil" in verse 4 is ra', meaning something bad, wrong or hurtful. And the word for "sin" in these verses, hata, means to miss the mark. All essentially imply deviating from a standard—that is, from God's standard.

In verse 4, David says to God, "Against You, You only, have I sinned." This might seem odd, for David appears also to have sinned against Bathsheba, Uriah, other soldiers who were killed in the battle in which Uriah died, and the nation of Israel, over which David had a responsibility to govern righteously. Jesus later said that one person can sin against another (Matthew 18:15). So what did David mean?

Some take it to be a matter of comparison. That is to say, what he did against these others is nothing compared to what he has done against God. Yet the answer is probably more a matter of nuance in perspective. Sin, we must consider, is the transgression of the law (1 John 3:4, KJV). Since God is the one who defines the law's standards, any violation of the law is against Him. Acting against another person is sin because God has set the rules of conduct forbidding this. The standard we have violated, the mark we have missed, is God's. In this sense, sin itself can only be against God, the Lawgiver. It would certainly be proper to say that one has sinned in acting against another person. And it is easy to see that the statement could be shortened to say that one has sinned against another person. But here we should realize that while the affected person is the object of the action that is sin, he is not the object of the sin (or transgressing) itself, as it was not his law that was transgressed but God's.

David's statement in Psalm 51:5 has caused much confusion: "Behold, I was brought forth in iniquity, and in sin my mother conceived me." This does not mean David's mother sinned in conceiving him. Nor does it mean that David was born stained with "original sin," as many maintain. Rather the Hebrew prefixed preposition b', usually translated "in," can also mean "into." As Gesenius' Hebrew and English Lexicon of the Old Testament says in one of its definitions of this word, it often occurs "with verbs of motion, when the movement to a place results in rest in it, into." Thus, David is most likely stating that he was brought forth into iniquity and into sin. As with all human beings, sin had characterized his life from a young age.

In verse 6, David says that God desires "truth in the inward parts, and in the hidden part...to know wisdom." It is one thing to know God's truth in an academic sense. It is quite another to also live by it in our inward thoughts and motivations. This, David knew, is what God really wants. And whenever we repent, we must consider what it is that God wants from us. It comes down to an educated change and a lifelong commitment—and that we follow through.

David asks God to "blot out," to "wash" and to "cleanse" him (verses 2, 9)—to thoroughly scrub him clean from His spiritual uncleanness (verses 6-7). In its note on verse 7, The Expositor's Bible Commentary states: "The unclean, such as lepers, used to present themselves before the priest on the occasion of their purification. The priest, being satisfied that the unclean person had met the requirements for purification, would take a bunch of 'hyssop' and sprinkle the person with water, symbolic of ritual cleansing. Here the psalmist [David] petitions the Lord to be his priest by taking the hyssop and by declaring him cleansed from all sin."

In this cleansing, David prays that God would create in him a clean heart and would renew a steadfast, faithful spirit within Him (verse 10). David realized he could not be faithful on His own. He needed God's constant help. So he pleads to remain in God's presence and to continue to have God's Holy Spirit to help him—not himself cast out and that Spirit taken away as he knew he deserved (verse 11).

Guilt over what he had done was always present in David's mind (verse 3). It took the joy and gladness out of life (verse 8). David figuratively refers to God having broken his bones (same verse), meaning that the overwhelming guilt he had from considering his sin in light of God's laws made him feel hobbled or crushed and greatly humbled. He prays to be forgiven and relieved of this guilt (verse 14)—and that His joy would return (verse 12).

David declares what he will do when God restores him. He will teach others God's ways (verse 13), He will sing about God's righteousness (verse 14)—no doubt in public psalms—and he will openly proclaim God's praise (verse 15). David was thinking outwardly, not selfishly about only himself. When we ask God for restoration, an important part of our motivation should be so that we can better serve Him and others.

In verses 16-19 we return to a major theme of Psalm 50—the kind of sacrifices God really wants (also touched on in Psalm 40). At the time he wrote, David was required to bring physical sacrifices to the tabernacle. And he no doubt did on this occasion soon after his confession before Nathan. Perhaps Psalm 51 was written as a song to accompany the sacrifice. Verse 16's statement about God not desiring sacrifice "or else I would give it" should not be understood to imply that David would not bring a sacrifice. The point is that he'll give God whatever God wants—he'll do whatever it takes—to be right with Him.

But David knows that God does not desire any physical sacrifices apart from the inner sacrifices of a right heart and mind—"broken," meaning humble, and "contrite," meaning repentant and obedient (verse 17). David used these same terms in Psalm 34:18. And the prophet Isaiah would later use them as well (Isaiah 66:2)—again in the context of the kind of sacrifices and service God is truly looking for. Psalm 51:19 uses the words "sacrifices of righteousness"—showing that it involves living the right way of life.

David concludes by asking God to "do good" to Zion or Jerusalem and to build its walls—meaning to bless and protect the people—including leading them to a right mindset—so that the people and their physical offerings would please Him (verses 18-19). This shows that God is pleased with physical offerings—but only when part of an inward devotion to Him and life of obedience. The holy city is likely here representative of the entire nation—and in a prophetic sense of spiritual Zion, the Church, as well as God's Kingdom in the world to come.

It should be noted that Psalm 51 has, thematically, many points of contact with Psalm 25.