The Ammonities, a neighbor nation of Israel, worshipped the gruesome god Moloch (his name means “king”).
In some worship sites an image of Moloch was heated like a furnace while slaughtered infants were placed in its arms and burned. The sacrifice was accompanied by cymbals and other noises—probably to drown out the children’s screams.
Most people of Israel—especially the prophets—were appalled at child sacrifice, even though it was fairly common in the ancient world. Many Israelites worshipped Moloch, something the prophets condemned.
Some of the kings, even the wise Solomon, set up worship sites for Moloch. The wicked king Manasseh sacrificed his own son to Moloch (2 Kings 21:6).
The favored site for the gruesome worship was the Valley of Ben Hinnom outside Jerusalem. The horrible spot had such a reputation that, in the period between the Old and New Testaments, some Jewish writers claimed that Ben Hinnom was the gateway to hell (see 870 [Gehenna]).