| Gill's Exposition of the Entire Bible I have pursued mine enemies, and destroyed them; and turned not again until I had consumed them. See Gill on Psalm 18:37.
Keil and Delitzsch Biblical Commentary on the Old Testament38 I will pursue my enemies and destroy them, I will not turn till they are consumed. 39 I will consume them and dash them in pieces, that they may not arise, And may fall under my feet. 40 And Thou girdest me with strength for war, Thou bowest mine adversaries under me. 41 And Thou makest mine enemies turn the back to me; My haters, I root them out. The optative form ארדּפה serves to make the future signification of ארדּף (in the psalm) the more apparent. Consequently it is quite out of the question to take the other verbs as preterites. We are not compelled to do this by the interchange of imperfects c. vav consec. with simple imperfects, as the vav consec. is not used exclusively as expressive of the past. On the contrary, the substance of the whole of the following description shows very clearly that David refers not only to the victories he has already won, but in general to the defeat of all his foes in the past, the present, and the future; for he speaks as distinctly as possible not only of their entire destruction (2 Samuel 22:38, 2 Samuel 22:39, 2 Samuel 22:43), but also of the fact that God makes him the head of the nations, and distant and foreign nations to him homage. Consequently he refers not only to his own personal dominion, but also, on the strength of the promise which he had received from God, to the increase of the dominion of the throne of his house, whilst he proclaims in the Spirit the ultimate defeat of all the enemies of the kingdom of God. This Messianic element in the following description comes out in a way that cannot be mistaken, in the praise of the Lord with which he concludes in 2 Samuel 22:47-51. ואשׁמידם, "I destroy them," is stronger than ואשּׂיגם, "I reach them" (in the psalm). In 2 Samuel 22:39 the words are crowded together, to express the utter destruction of all foes. In the psalm ואכלּם is omitted. ותּזרני for ותּאזּרני in the psalm is not a poetical Syriasm, and still less a "careless solecism" (Hupfeld), but a simple contraction, such as we meet with in many forms: e.g., מלּפנוּ for מאלּפנוּ (Job 35:11; cf. Ewald, 232, b.). The form תּתּה for נתתּה (in the psalm) is unusual, and the aphaeresis of the נ can only be accounted for from the fact that this much-used word constantly drops its נ as a radical sound in the imperfect (see Ewald, 195, c.). The phrase ערף לּי תּתּה is formed after Exodus 23:27. "Giving the enemy to a person's back" means causing them to turn the back, i.e., putting them to flight.
Geneva Study BibleI have pursued mine enemies, and destroyed them; and turned not again until I had consumed them.
Matthew Henry's Concise Commentary22:1-51 David's psalm of thanksgiving. - This chapter is a psalm of praise; we find it afterwards nearly as Ps 18. They that trust God in the way of duty, shall find him a present help in their greatest dangers: David did so. Remarkable preservations should be particularly mentioned in our praises. We shall never be delivered from all enemies till we get to heaven. God will preserve all his people, 2Ti 4:18. Those who receive signal mercies from God, ought to give him the glory. In the day that God delivered David, he sang this song. While the mercy is fresh, and we are most affected with it, let the thank-offering be brought, to be kindled with the fire of that affection. All his joys and hopes close, as all our hopes should do, in the great Redeemer. | 
