Charles Ellicott Commentary Ezekiel 20:26

"and I polluted them in their own gifts, in that they caused to pass through [the fire] all that openeth the womb, that I might make them desolate, to the end that they might know that I am Jehovah." — Ezekiel 20:26 (ASV)

To pass through the fire. — The word “fire” here, as in Ezekiel 16:21 and Ezekiel 23:37, is not in the original, but is rightly supplied from Ezekiel 20:31. The custom referred to was probably that of consecrating their seed to Moloch, expressly forbidden in Leviticus 20:1-5. (Compare to Acts 7:43.) The causing children to pass through the fire continued as a common sin even to the later days of the monarchy (2 Kings 17:17 and 2 Kings 21:6).