John Gill

Give them according to their deeds,.... According to the demerit of them, which is death, even death eternal; and according to the wickedness of their endeavours; for though wicked men do not always succeed; yet their want of success does not excuse their wickedness; give them after the work of their hands; see Ti2 4:14; render to them their desert; what their iniquities, in thought, word, and deed, deserve: such petitions are not contrary to that Christian charity which the Gospel recommends; nor do they savour of a spirit of revenge, which is condemned by the word of God; for it should be observed, that these things are said with respect to men given up to a reprobate mind; and that the psalmist does not seek to avenge himself, nor to gratify his own mind; but he sought the glory of God, and moreover spoke by a prophetic spirit, knowing what was the will of God in this case; see Psa 28:5; and therefore these petitions of his are not to be drawn into an example in common and ordinary cases.