John Gill Bible Commentary

They have also built the high places of Baal,.... Or, they have even built, &c. and so the words explain what is before suggested of their idolatry; these were the temples in which they placed his image, and the altars on which they sacrificed to him; as follows: to burn their sons with fire, for burnt offerings unto Baal; the same idol that is sometimes called Moloch, the names being much of the same signification; the one signifying a "lord" or "master"; the other a king; and to the idol under each name they burned their children with fire, and offered them as burnt offerings unto it; which was a most cruel and barbarous way of sacrificing. Some think they only caused them to pass through two fires; but the text is express for it, that they burnt them with fire, and made burnt offerings of them, as they did with slain beasts. It seems very likely that they did both: which I commanded not; in my law, as the Targum adds; and which was intimation enough to avoid it; though this was not all, he expressly forbad it, Lev 20:2; nor spake it, neither came it into my mind; and it is marvellous it should ever enter into the heart of man; none but Satan himself could ever have devised such a way of worship.