Deuteronomy 7 · a question people ask
If the nations were to be utterly destroyed (7:2), why does the very next verse forbid marrying them?
The chapter itself says the nations would not be gone at once: "The LORD your God will cast out those nations before you little by little. You may not consume them at once" (7:22). It speaks of "those who are left, and hide themselves" (7:20). The LORD had said the same at Sinai: "Little by little I will drive them out from before you" (Exodus 23:30), and there too the command follows, "You shall make no covenant with them, nor with their gods" (Exodus 23:32). When Joshua was old, he called all Israel together (Joshua 23:1-2) and took up the same things side by side: "if you do at all go back, and hold fast to the remnant of these nations, even these who remain among you, and make marriages with them… they shall be a snare and a trap to you" (Joshua 23:12-13). The chapter doesn't say more than this about how the commands fit together.
The verses
“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. 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.”
“Moreover the LORD your God will send the hornet among them, until those who are left, and hide themselves, perish from before you.”
“The LORD your God will cast out those nations before you little by little. You may not consume them at once, lest the animals of the field increase on you.”
“I will not drive them out from before you in one year, lest the land become desolate, and the animals of the field multiply against you. Little by little I will drive them out from before you, until you have increased and inherit the land. I will set your border from the Red Sea even to the sea of the Philistines, and from the wilderness to the River; for I will deliver the inhabitants of the land into your hand, and you shall drive them out before you. You shall make no covenant with them, nor with their gods.”