Deuteronomy 7:2-6

and when Jehovah thy God shall deliver them up before thee, and thou shalt smite them; then thou shalt utterly destroy them: thou shalt make no covenant with them, nor show mercy unto them; neither shalt thou make marriages with them; thy daughter thou shalt not give unto his son, nor his daughter shalt thou take unto thy son. For he will turn away thy son from following me, that they may serve other gods: so will the anger of Jehovah be kindled against you, and he will destroy thee quickly. But thus shall ye deal with them: ye shall break down their altars, and dash in pieces their pillars, and hew down their Asherim, and burn their graven images with fire. For thou art a holy people unto Jehovah thy God: Jehovah thy God hath chosen thee to be a people for his own possession, above all peoples that are upon the face of the earth.