David confounded, Christ Jesus blessed:

King James Version Psalm 40

14  gLet them be ashamed and confounded together that seek after my soul to destroy it;

Let them be driven backward and put to shame that wish me evil.

New American Bible: Revised Edition Chapter 6

28 bless those who curse you, pray for those who mistreat you.t

New American Bible: Revised Edition Chapter 12

14 *Bless those who persecute [you],k bless and do not curse them.l

Christ Jesus says, “To those who hear?” So what are we to hear in these testimonies: one thing that may be heard or recognized is a possible difference between what King David is saying, in this Psalm, and what Christ Jesus teaches, and then, Saint Paul re-expresses.

David says confound those and let them be ashamed, speaking of those who sought after King David’s destruction; whereas, Christ Jesus says, “Bless those who curse us,” and there seems to be a conflict, that is, until you realize: when a person is ashamed for their wicked and evil behavior, there is a chance that they may recognize their wrongheadedness Romans 2:4 and then, choose to turn to the Lord God, the God of Jacob-Israel, the creator of heaven and earth. Now when King David is expressing, in prayer to the Lord… that those who seek after his soul, his life, please confound them, this too is an iteration in the intention of getting their attention, so that they may turn away from their disobedience to God our Heavenly Father and be once again living in obedience with God our Heavenly Father, which is the only place that man has peace with himself and harmony with life, life is, our Lord Christ Jesus, Christ Jesus being the way, the truth, and the life....

So, when we first read this, it may suggest a conflict of teachings, but upon meditation and the realization of what shame is and what is being confounded also is, then we know that King David likewise was blessing those who seek after his soul to destroy him....

Okay, if King David would have been returning evil for evil or curse for curse, David, the kings prayer would not have been of confound and shame toward these people; rather it would have been for their complete annihilation, which is something King David was not praying in this psalm.

Again, we should say, as The Lord God, the God of Jacob-Israel employed, Nebuchadnezzar to destroy the Israelites for their wickedness: for the Israelites immoralities, at the time of the dispersion, were worse than Sodom and Gomorrah, so also did God the Heavenly Father employ, King David to destroy the Philistines and many other tribes of people who had ran their course of wickedness and their time was up....