ספֿרי מצוות אויף דברים 7:2

It is a Positive Commandment to exterminate the Seven Nations, as it says, “surely, you shall destroy them” (Deut. 20:17). Anyone who comes across any of these nations and fails to kill them violates a Negative Commandment, as it says, “you shall not keep alive any soul” (Deut. 20:16). Nonetheless, they have already all been destroyed and their memory forgotten.

Gimel. Their [Canaanite] nations- do not make treaties with them

To exterminate the seven Canaanite nations from the land of Israel, as it is said, “But thou shalt utterly destroy them….” (Deut. 20:17).