John Gill Commentary Deuteronomy 6:19

"to thrust out all thine enemies from before thee, as Jehovah hath spoken." — Deuteronomy 6:19 (ASV)

To cast out all your enemies from before you
This the Lord promised, and as it seems with an oath, that he would do for them; drive out their enemies, and make way for the settlement of them in their country:

as the Lord has spoken ;
see (Genesis 15:18Genesis 15:19Genesis 15:20) (22:17) (Exodus 23:28) .