Deuteronomy 31:4
And the LORD shall do unto them as he did to Sihon and to Og, kings of the Amorites, and unto the land of them, whom he destroyed. And the LORD shall do unto them as he did to Sihon and to Og, kings of the Amorites, and unto the land of them, whom he destroyed.
The verse belongs to Moses's closing instruction in Deuteronomy chapters 22 to 34, which is solemn, hopeful, cheering, and earnest while pointing out the awful responsibilities and fearful curses of transgression. Within that closing portion it stands in the record of Moses's final charge, the delivery of the law to the priests, and the commission to Joshua. It assures Israel that the Lord would defeat the peoples of Canaan in their path as he had defeated Sihon and Og, kings of the Amorites, destroying their land and dispossessing it.