Jerome, some early history may help you understand. Centuries earlier Abraham was promised his offspring would inherit the promised land.
(Genesis 15:13-16) And he began to say to A'bram: “You may know for sure that your seed will become an alien resident in a land not theirs, and they will have to serve them, and these will certainly afflict them for four hundred years.?But the nation that they will serve I am judging, and after that they will go out with many goods. ?As for you, you will go to your forefathers in peace; you will be buried at a good old age.?But in the fourth generation they will return here, because the error of the Am'or·ites has not yet come to completion. In order to keep the nation of Israel free of the contaminating influence of the depraved nations they were dispossessing no alliance with them was allowed.They were to be subject only to God’s laws and statutes, not to those of the nations due for eviction. (Le 18:3, 4; 20:22-24) They were particularly warned against forming marriage alliances with such nations. Such alliances would intimately involve them not only with pagan wives but with pagan relatives and their false religious practices and customs, and this would result in apostasy and a snare.—De 7:2-4; Ex 34:16; Jos 23:12, 13. In the battle with Midian, the Israelites preserved alive only virgins from among the women and girls. (Nu 31:3, 18, 35) The Law allowed for the taking of a wife from among such parentless female war captives. (De 21:10-14) Within the Promised Land itself God’s warning concerning marriage alliances with pagans was often ignored, with resulting problems and apostasy.—Jg 3:5, 6.
