In Numbers, there's an interesting episode involving the genocide of the Midianites. Some of the Israelites covet the land of the Midianites since it is especially good for livestock, and they decide to take it even though it is not part of the so called Promised Land. They promise to fight for the Promised Land when the time comes, but they aim to live in the land of the Midianites. To this end, they attack the Midianites and kill all the adult men and take all the women and children captive. The Israelite leadership chastises them and requires them to kill every male child and every female that has ever had sex. Only virgin females are to be spared.
Evidently, at one time genocide was an approved policy of the God of Abraham, Isaac and Israel. Perhaps it was even a method God employed to work His will in the world. I suppose it made rational sense if you wanted to be sure no Midianite was around to exact vengeance and if you aimed to rid yourself of alien cultural influences, but it doesn't seem right when judged by our modern moral sensibilities. The authors of Numbers seem downright proud of the slaughter of the Midianites.
I sometimes hear it said that God is the same yesterday, today and tomorrow. I'm hoping He has dropped genocide from His list of approved activities and that He is not the same as the God of Numbers, if He ever was..