I’m not an expert like Dr. J, but from what I remember, there were no human/child sacrifices under the Mosaic law. The Israelites did ften offer their firstborn as sacrifices, though, in Old Testament times, in worship to Baal/Molech. From what I’ve been told, Baal was a fertility God, and the sacrifice of the firstborn was to supposedly ensure future kids.
That was one of the reasons, I was told, that the prophets of the Old Testament (Elijah, etc.) hated Baal worship so much.
