Any Israelite who sacrificed to another god was to be put to death.
We previously established that GOD forbid idolatry and any worship of other gods besides Himself. The punishment for sacrificing to other gods was death:
19 He who sacrifices to any god except to the Lord alone, he shall be put to death.Exodus 22:19 [22:20] OSB
GOD would not tolerate rebellion then, and He will not let it go unpunished today.