Psalms 51:14

I. David prays against the guilt of sin, and prays for the grace of God, enforcing both petitions from a plea taken from the glory of God, which he promises with thankfulness to show forth. 1. He prays against the guilt of sin, that he might be delivered from that, and promises that then he would praise God, Psa 51:14. The particular sin he prays against is blood-guiltiness, the sin he had now been guilty of, having slain Uriah with the sword of the children of Ammon. Hitherto perhaps he had stopped the mouth of conscience with that frivolous excuse, that he did not kill him himself; but now he was convinced that he was the murderer, and, hearing the blood cry to God for vengeance, he cries to God for mercy: "Deliver me from blood-guiltiness; let me not lie under the guilt of this kind which I have contracted, but let it be pardoned to me, and let me never be left to myself to contract the like guilt again." Note, It concerns us all to pray earnestly against the guilt of blood. In this prayer he eyes God as the God of salvation. Note, Those to whom God is the God of salvation he will deliver from guilt; for the salvation he is the God of is salvation from sin. We may therefore plead this with him, "Lord, thou art the God of my salvation, therefore deliver me from the dominion of sin.

— Matthew Henry's Concise Commentary (public domain)

Deliver--or, "Free me" (Psa 39:8) from the guilt of murder (Sa2 12:9-10; Psa 5:6). righteousness--as in Psa 7:17; Psa 31:1.

— Jamieson-Fausset-Brown Commentary (public domain)