I. (51:1–2) Have Mercy on Me. The psalm opens with an appeal to God for forgiveness. The terms “mercy” and “steadfast love,” as well as “transgressions,” “iniquity,” and “sin,” all evoke God’s proclamation of his own name (Ex. 34:6–7), with its focus on his grace and kindness: “The Lord passed before [Moses] and proclaimed, ‘The Lord, the Lord, a God merciful and gracious, slow to anger, and abounding in steadfast love and faithfulness, keeping steadfast love for thousands, forgiving iniquity and transgression and sin.’”438

The plea for mercy here is a humble one, based entirely on God’s mercy, frankly recognizing that the worshiper does not deserve it. The worshiper has his wrongdoings, while he trusts the Lord’s declaration of his fundamentally benevolent stance toward his faithful.439

The poet has structured these verses in a chiasmus:

Have mercy on me, O God,

according to your steadfast love;

according to your abundant mercy

blot out my transgressions.

The first terms (“mercy,” “steadfast love”) are more general terms for God’s generous stance toward his people, while the second two increase the intensity (“abundant mercy”) and focus on the specific kind of generosity in view here (“blot out”). The term “blot out” uses the imagery of a record book, with the entry being wiped away and no longer available for consultation (cf. Pss. 9:5; 51:9; 69:28; contrast 109:14; cf. also Acts 3:19; Col. 2:14).

The terms “wash” (cf. Ex. 19:10) and “cleanse” (cf. Num. 19:19) come from the ceremonial system, in which they refer to rites that allow a person to come safely into God’s presence. In the Levitical system not all uncleanness is sin, but sin does make a person unclean. For an unclean person to come boldly into God’s presence without the intention of remedying the uncleanness is deeply offensive to God—thus the ceremonies serve human well-being. Here the psalm focuses on the inner condition the ceremony is intended to mediate.

II. (51:3–5) I Own Up to My Sin. The next section builds on the humility of the opening section, freely acknowledging that the sin is the worshiper’s own and that God is free from all blame. Indeed, God would be fully justified in refusing the request for mercy and in bringing judgment instead.

“My sin is ever before me” (Ps. 51:3), in the context of this psalm’s internality (cf. Section Overview and Outline), describes the singer’s constant inner awareness of having done wrong. Since this is a song to be sung by a congregation of real people, no doubt not everyone in the assembly feels this awareness as deeply as is proper; the goal of this section is to promote a deeper and more serious sense of each person’s own faults.

In verse 4 the singer declares, “Against you, you only, have I sinned.” Of course, in doing wrong he has hurt others, and the Psalms readily grapple with the communal effects of good and bad deeds (as this one will in vv. 18–19). The point here, though, is that God is the ultimate judge for all sin—and this gives not less weight but more to the harm caused to others, since God is their advocate and avenger (Prov. 17:5; 19:17; 21:13; 29:14, with the poor person as an example of the vulnerable). Thus when Nathan confronts David over the sin with Uriah and Bathsheba (as in the title to this psalm) his response is “I have sinned against the Lord” (2 Sam. 12:13), which hardly excludes his sense of responsibility to those he has hurt.

The second half of Psalm 51:4 acknowledges that this is “so that you may be justified in your words and blameless in your judgment.” The psalmist owns up to his guilt before God “so that” God’s justice in all he does will be clear. As Delitzsch puts it, “It is just the nature of penitence so to confess one’s self to be in the wrong in order that God may be in the right and gain His cause.”440 In Romans 3:4 Paul cites this part of the verse from the LXX in support of his argument that God is just and entitled to judge human beings.

In verse 5 the psalmist continues, “I was brought forth [i.e., from the womb] in iniquity.” The song has each singer thinking of himself or herself as a sinful person from the time of his or her birth. Further, “in sin did” the singer’s “mother conceive” him. Some may read this as stating that the act of conception was itself sinful, but its import is rather (as the parallel first line shows) to have each worshiper learn to trace his sinful tendencies to the very beginning of his existence—not only from birth but from even from before that, to conception.441

The psalm itself does not address the question of why the sinful tendencies are present, even from conception, since this is not the focus of attention. Nevertheless, some notion of man’s “fall,” as traditional readings of Genesis 3 have it, provide the best explanation for this overall situation, in which “the intention of man’s heart is evil from his youth” (Gen. 8:21).442

III. (51:6–12) I Seek Restoration and Renewal. The proper posture of the penitent is to crave a fresh sense of God’s presence (Ps. 51:8–9, 11) and a deeper purification of the moral life (vv. 6, 10, 12). With the terms “inward being,” “secret heart” (v. 6), “clean heart,” and “right spirit” (v. 10), the song places its focus on the inmost self, from which obedient actions flow. The song invites its singer to pursue not self-abasement but rather a renewal of the joy and gladness (v. 8) that the faithful enjoy in God’s presence.

“Hyssop” (v. 7) is a plant of uncertain identification; we may assume that it had hairy leaves and branches, so that bunches of the branches were good for sprinkling.443 For its use in a cleansing ceremony cf. Leviticus 14:6; Numbers 19:6. As with Psalm 51:2 (cf. comment on 51:1–2), the psalm highlights the inner condition the ceremonies mediate. The next verse continues this endorsement of physicality, with its mention of “bones”: the feeling of God’s displeasure, as well as of his favor, penetrates into the whole person (32:3).

Usually when God is said to “hide” his “face” from someone (51:9) it means that he will no longer look upon that person with favor (Deut. 31:17; 32:20; Pss. 13:1; 22:24; 27:9; 88:14; 102:2; 143:7; Isa. 8:17; 54:8; 59:2; 64:7).444 Here the parallel with “blot out” shows that the singer asks God no longer to look upon his sins. (For the term “blot out” cf. comment on 51:1–2).

Verse 10 asks for God to “create” a clean heart. The Hebrew verb (baraʼ) generally carries the nuance of “make a fresh beginning,” though of itself it need not imply “start from scratch” (that comes from the context). Here its parallel is “renew.”445

Verse 11 prays, “Take not your Holy Spirit from me.” Theological discussions have revolved around the question of whether the Holy Spirit can be taken from someone in the OT—with a bearing on specifically Christian approaches to whether one can “lose” the Holy Spirit’s indwelling by unfaithfulness.446 Thus some take this text to imply that the Holy Spirit can indeed be taken from someone, at least in the OT; others have suggested that the Holy Spirit is viewed here in his role of empowering David for his kingly duties and that this is a prayer for God not to take the kingship or the divine anointing for kingship from David, as he did from Saul (1 Sam. 16:13–14).447 To make sense of the expression we should first observe that the OT rarely discusses the Holy Spirit’s role in cleansing the inner life—Ezekiel 36:27 is the only clear reference on the subject. The Hebrew Bible certainly does not enter into technical questions of the Spirit’s permanent indwelling. Now, the fact that this is a psalm for the whole congregation argues against the idea that this is David’s personal prayer about his kingship. Certainly a serious person would pray that God would not remove his empowering and guidance from David, but the psalm is not about David as such; each member of the congregation is identifying with the “I” of the psalm.

Rather, the tenor of this psalm is that if strict justice were God’s only consideration, he would have the right to bring dire judgment on those who sin (which includes all of his own people), and that the only possible appeal is to his mercy. Were the song to engage in technical theologizing (and thus cease to be poetry!), it would run something like this: “I know that by my misdeeds I deserve for you to remove all signs of your love toward me, your Holy Spirit included; please show me mercy rather than giving me what I deserve.”

The function of the psalm, as a song sung together, is to shape the hearts of those who sing it so that they feel this at the deepest level, lest they ever presume upon God’s grace. As Kidner puts it, “This verse is not concerned with the bare doctrine of perseverance but with the practice of it.”448

IV. (51:13–17) Then I Will Worship Truly. The terms in this section, such as “sing aloud” (v. 14), “declare” (v. 15), and “sacrifice” (vv. 16–17), all designate activities of public worship. Probably “teach” (v. 13) also envisions a liturgical setting: by joining with the faithful in song and prayer the members teach one another (32:8; Col. 3:16). The person who has used Psalm 51 to confess his or her sins and to receive God’s assurance of pardon is the one who can genuinely worship the gracious God of the covenant.

As usual in the Psalms, the “transgressors” and “sinners” (Ps. 51:13) are members of the covenant people who do not faithfully embrace the provisions of God’s covenant. The song envisions them as being present in the worshiping assembly, and the faithful call them to embrace God’s grace, from the perspective of those who themselves deserve to be cast out.

The term “bloodguiltiness” (v. 14) is probably a reference to the slaying of Uriah (cf. 2 Sam. 12:9). Most of the faithful (one hopes) will not have committed this particular sin, but the rhetorical force of mentioning it here is so that they will both accept the depth and seriousness of their own sinfulness and also take heart by reasoning that if God can forgive David this evil, then we can certainly count on him to forgive all else!

Psalm 51:16–17 seem to make “sacrifice” and “burnt offering” relatively unimportant for the faithful, even replacing them with the inner disposition (“a broken spirit . . . a broken and contrite heart”). Since verse 19, however, goes on to speak of offering actual sacrifices, it is better to take these verses as implying that ideally the worshiper uses the animal sacrifices as a way of offering himself to God (cf. Section Overview and Outline) as a “living sacrifice” (Rom. 12:1); without this intention the sacrifices lose all benefit and become positively harmful.

V. (51:18–19) Do Good to Zion. The psalm closes by enabling worshipers to see the relationship between their own spiritual health and the well-being of the whole body of God’s people (“Zion” and “Jerusalem”). That is, each member is linked to all the others in a web of relationships, and together they share in the life of God as it pulses through the whole body. Thus each member contributes to (or else detracts from) the health of the whole. The ideal Israel is a community of forgiven penitents, faithfully embracing God’s covenant and worshiping him according to the rites he has appointed; this is the community that can bring light to the whole world. (This outlook, by the way, shows why there is no need to agree with some commentators who treat these closing two verses as an addition to the psalm.449)

Some take the verb in verse 18 (“build up”) as “rebuild” (NRSV; NLT). The Hebrew verb simply means “to build,” and sometimes it is used at places with rebuilding in view. If we take the title seriously there is no need to find the context to be pointing that way. Rather, the verse uses an image that Christian readers will find familiar: “build up” in the sense of “strengthen in the moral and spiritual life” or “edify” (from the Latin equivalent to “build up”). Here the “walls” of Jerusalem are what the people present to the outside world (in some cases to invading Gentiles!). But the poetry seems to invite its singers to think more broadly of the kind of life that should go on within those walls, which leads to the image of “edification.” Other possible uses of this image in the OT include 69:35; 102:16; 147:2; Proverbs 14:1.450 In the NT we read of the church’s being built or built up (Matt. 16:18; Acts 9:31; 1 Cor. 3:9; Eph. 2:21; 1 Pet. 2:5), which then gets extended to the various members’ being built up (Acts 20:32; Rom. 14:19; 15:2; 1 Cor. 8:1; 10:23; 14:3–5, 12, 17, 26; 2 Cor. 10:8; 12:19; 13:10; Eph. 4:12, 16, 29; 1 Thess. 5:11).