Charles Ellicott Commentary Deuteronomy 33:29

"Happy art thou, O Israel: Who is like unto thee, a people saved by Jehovah, The shield of thy help, And the sword of thy excellency! And thine enemies shall submit themselves unto thee; And thou shalt tread upon their high places." — Deuteronomy 33:29 (ASV)

Thine enemies shall be found liars unto thee.—See Psalms 66:3: Through the greatness of thy power shall thine enemies submit themselves (i.e., lie) unto thee. The idea is, that the enemies of the conqueror will hasten to throw themselves at his feet, protesting that they were always his friends. (Compare Shimei’s repentance on the occasion of David’s return to Jerusalem, 2 Samuel 19:18.)