To explain this, i should clarify. God used not ok with humans killing children for their own reasons. If God is passing judgement on a people, that is differnt. Also, Christ is very clear, every man involved in plural marriage is commiting adultery because each man can only have 1 wife. But, ultimately, that is not important because all people have sinned, and falen short if the standard of perfection we mudt acheive. That is why Christ came down from Heaven and became a human, lived a perfect life, and sacrificed hinself to save us! ALL who believe him will be saved.