[Ahaz] walked in the way of the kings of Israel. He even burned his son as an offering, according to the despicable practices of the nations whom YHWH drove out before the people of Israel.
2 Kings 16:3

It's not clear whether Ahaz actually sacrificed his child or performed some kind of dedication ritual involving fire. In either case, it was idolatrous and wicked, and human sacrifice has been a feature of almost all pagan religions throughout history.