Ahaz commits idolatry
Ahaz king of Judah committed idolatry, including sacrificing his sons in the Valley of Hinnom.
Key passages
2 Ki 16:3–4

He walked in the way of the kings of Israel; he even let his son pass through the fire according to the detestable things of the nations which Yahweh drove out from before the Israelites. He sacrificed and offered incense on the high places, on the hills, and under every green tree.

2 Ch 28:2–4

But he walked in the ways of the kings of Israel and also made molten idols for the Baals. And he himself burned incense in the valley of Ben-Hinnom and burned his sons in the fire, according to the detestable practices of the nations whom Yahweh drove out before the Israelites. And he sacrificed …

See also
Important Things