For thy name’s sake, O Lord - See the notes at Psalms 23:3. The idea here is that God would do this on His own account, or for the honor of His own name. This is A reason, and one of the main reasons, why God ever pardons iniquity. It is that the honor of His name may be promoted; that His glorious character may be displayed; that he may show himself to the universe to be merciful and gracious. There are, doubtless, other reasons why He pardons sin - reasons drawn from the bearing which the act of mercy will have on the welfare of the universe; but still the main reason is, that His own honor will thus be promoted, and His true character thus made known. See the notes at Isaiah 43:25; notes at Isaiah 48:9. Compare Psalms 6:4; and Psalms 25:7.
Pardon mine iniquity - This prayer seems to have been offered in view of the remembered transgressions of his early years, Psalms 25:7. These recollected sins apparently pressed upon his mind all through the psalm, and were the main reason of the supplications which occur in it. Compare Psalms 25:16-18.
For it is great - As this translation stands, the fact that his sin was great was a reason why God should pardon it. This is a reason, because:
(a) it would be felt that the sin was so great that it could not be removed by anyone but God, and that unless “forgiven” it would sink the soul down to death; and
(b) because the mere fact of its magnitude would tend to illustrate the mercy of the Lord.
Undoubtedly, these are reasons why we may pray for the forgiveness of sin; but it may be doubted whether this is the exact idea of the psalmist, and whether the word “although” would not better express the true sense - “although it is great.” It is true that the general sense of the particle here rendered “for” - כי kı̂y - is “because” or “since;” but it may also mean “although,” as in Exodus 13:17, “God led them not the way through the land of the Philistines, although - (כי kı̂y) - that was near,” that is, that was nearest, or was the most direct way. So in Deuteronomy 29:19, “I shall have peace, though - (כי kı̂y) - I walk in the imagination of mine heart.” Also Joshua 17:18, “Thou shalt drive out the Canaanites, though - (כי kı̂y) - they have iron chariots, and though they be strong.” Thus understood, the prayer of the psalmist here is, that God would pardon his offences “although” they were so great. His mind is fixed upon the “greatness” of the offences; upon the obstacles in the way of pardon; upon his own unworthiness; upon the fact that he had no claim to mercy; and he presents this strong and earnest plea that God would have mercy on him “although” his sins were so numerous and so aggravated. In this prayer all can join; this is a petition the force of which all true penitents deeply feel.