Have mercy upon me, O God, according to thy lovingkindness: according unto the multitude of thy tender mercies blot out my transgressions.
Psalms 32:1-11 was written AFTER this Psalms 51:1-19, before David's adultery with Bathsheba and murder of Uriah. Since there he invites all to share with him the blessing of experienced forgiveness by heartily confessing sin, so here he seeks it, and promises, in the event of receiving it, to teach other transgressors the way of peace.
Psalms 51:1-19.-Prayer resting on confession of actual and original sin (Psalms 51:1-6); purification sought, and the gift of the Spirit (Psalms 51:7-12); thanksgiving promised, and the conversion of sinners through his testimony, when he shall be restored to the joy of God; praise and contrition God loves more than sacrifice; these he and the people will offer when God shall do good to Zion and her king (Psalms 51:13-19).
Title. - To the chief Musician. Marvellous that the highest personage in the kingdom should thus publicly proclaim His heinous sin and subsequent penitence! So grateful had grace made him for pardon, that he desired to make his case (however natural inclination might shrink from it) an instructive lesson to all the people of God whom he had offended by his sin. His penitential psalm, sung in the public service of the temple, would proclaim far and wide the path to pardon for the worst sinners.
A Psalm of David, when Nathan the Prophet came unto him, after he had gone in to Bathsheba. Instead of "after," translate х ka'ªsher (H834)] 'according as.' It is not here a particle of time; because Nathan's coming to David was about a year subsequent to David's connection with Bathsheba (2 Samuel 12:14-15). The use of the same verb and preposition х bow' (H935) + 'el (H413)] in both clauses implies that the connection between David's going to Bathsheba and Nathan's going to David is that inseparable connection which there is between sin and its condemnation. Translate the verbs alike: 'When Nathan the prophet had gone unto him, after he had gone unto Bathsheba.' Especially in the case of the godly, sin is followed by chastisement, not only because of God's anger, but chiefly because of God's love (cf. Leviticus 10:3; Amos 3:2; 1 Peter 4:17).
Have mercy upon me, O God. He does not venture to call Him 'my God;' but he appeals to God in respect to His own attributes.
According to thy loving-kindness; according unto the multitude of thy tender mercies blot out my transgressions. "The multitude of thy tender mercies" is needed because of the multitude of my sins (Isaiah 55:7, margin; Psalms 130:7). His sin, in the case of Uriah and Bathsheba, presents itself now before his awakened conscience as not merely one sin, but an accumulation of sins; therefore he uses the plural: his many acts of adultery with Bathsheba, his shedding the bled of Uriah, and of three who perished with him, his impenitence and hypocrisy for nearly a year, and the occasion which he had given for the enemies of God to blaspheme against all religion. "Blot out," here and Psalms 51:9, is an image from erasing a debt out of an account-book. Our sins are debts entered into the book of God's remembrance against the judgment, and can be blotted out only by that Saviour who 'blotted out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to His cross' (Colossians 2:14; Isaiah 43:25; Isaiah 44:22). David's expression refers to Nathan's declaration, 2 Samuel 12:13, "The Lord also hath put away (literally, caused to pass х he`ªbiyr (H5674)]) thy sin." Though Nathan had thus announced an immediate and full pardon to David on his brief confession of sin, yet the penitent was not able at once to appropriate it. The greater had been the grace conferred on him, the deeper was his fall, and the harder did he find it to reach a state of peace. The promise of pardon only kept him from despair; but before he could attain to joyful assurance, he had to pass through deep waters of self-loathing because of his enormous sin. Not that God's grace did not hold out immediate peace, but that his faith, impaired by the consciousness of sin, was slow to lay hold of it.