*Minor differences ignored. Grouped by changes, with first version listed as example.
What can David say more - How can I express my endless obligation to thee?
And what can David say more unto thee,.... In a way of self-abasement, or in thankfulness for such wonderful favours, or in prayer for more and other mercies; he wants words, as if he should say, to express his sense of his own nothingness and unworthiness, and to praise the Lord for all his benefits; and so large are the grants and promises made, that there is no room for him to ask for more:
for thou, Lord God, knowest thy servant; what a sense he has of his own meanness and vileness, what gratitude his heart is filled with, and what his wants and necessities are, which God only can supply, and does abundantly, even more than he is able to ask or think. The Targum is,"and thou hast performed the petition of thy servant, O Lord God.''
what can David say more unto thee?--that is, my obligations are greater than I can express.
"And what more shall David speak to Thee? Thou knowest Thy servant, Lord Jehovah." Instead of expressing his gratitude still further in many words, David appeals to the omniscience of God, before whom his thankful heart lies open, just as in Psalm 40:10 (compare also Psalm 17:3).
David say - Either in a way of gratitude and praise, words cannot express my obligations to thee, nor my sense of these obligations: Or in a way of prayer. What can I ask of thee more than thou hast freely done? Thou knowest - Thou knowest my deep sense of thy favours, and my obligations to thee. And my condition and necessities, what I do or may need hereafter; and as thou knowest this, so I doubt not thou wilt supply me.
*More commentary available at chapter level.