The third prohibition is, Thou shall not let any of thy seed pass through the fire to Molech. The words the fire are properly inserted, though not expressed in the original (cf. Deuteronomy 18:10; 2 Kings 22:10).
What was the nature and purpose of the idolatrous rite in question is, however, uncertain. It is generally assumed that reference is made to the practice of offering children in sacrifice to Molech, Deuteronomy 12:31, Ezekiel 16:20, and Psalms 106:37 being quoted in support of that view.
But it is by no means certain that this was the case. It might have been a rite by which children were dedicated to Molech—a baptism by fire, not resulting in the death of the child. Its mention here, in close connection with carnal sins, has led some to regard it as an impure rite; but this is a mistaken inference, for the prohibition of adultery naturally suggests the prohibition of a spiritual unfaithfulness.
That it was some kind of idolatrous ceremony is shown by the addition of the words, neither shalt thou profane the name of thy God. But if the children were burnt to death in honour of the idol, from the beginning, we should expect to find a notice of the fact in less ambiguous language than the expression, pass through the fire, conveys, earlier than the days of Ahaz.
It is easy to imagine that what began as a dedication ceremony may have become converted into an absolute sacrifice, retaining still its original designation. Molech was a Canaanitish and Phoenician deity, the name meaning King, just as Baal means Lord (see Selden, 'De Diis Syris,' Psalms 1:6).
Jarchi, quoted by Wordsworth, describes the idol as "made of brass, having the face of an ox, with arms stretched out, in which the child was placed and burnt with fire, while the priests were beating drums, in order to drown the noise of its shrieks, lest the fathers might be moved with pity thereby."
The place where the children were offered, in the later period of the Jewish history, was the valley of Hinnom (Jeremiah 7:31; Jeremiah 32:35; 2 Kings 23:10).