Deuteronomy 7:2 in the King James Version
And when the LORD thy God shall deliver them before thee; thou shalt smite them, and utterly destroy them; thou shalt make no covenant with them, nor shew mercy unto them:
Context
1 When the LORD your God brings you into the land where you go to possess it, and casts out many nations before you—the Hittite, the Girgashite, the Amorite, the Canaanite, the Perizzite, the Hivite, and the Jebusite—seven nations greater and mightier than you;
2 and when the LORD your God delivers them up before you, and you strike them, then you shall utterly destroy them. You shall make no covenant with them, nor show mercy to them.
3 You shall not make marriages with them. You shall not give your daughter to his son, nor shall you take his daughter for your son.