What does God say to the Israelites that would foretell victory over their enemies?

Many verses. Here are just two:

My angel shall go before you, and bring you into the (land of the) Amorite, and the Hittite, and the Perizzite, and the Canaanite, the Hivite, and the Jebusite; and I will cut them off (Exodus ch.23).

And:

(Deuteronomy ch.1) The Lord our God spoke unto us in Horeb, saying: 'You have dwelt long enough in this mountain; turn, and journey and go to the hills of the Amorites and all their neighbors, in the southern lowland, the hill-country, the plain, the Negev, and the sea-shore; the land of the Canaanites, and the Lebanon, as far as the Euphrates. Behold, I have laid the land in front of you: go in and possess the land that the Lord swore unto your fathers Abraham, Isaac, and Jacob, to give unto them and to their seed after them.'