Milcom was the false god of the Ammonites, whose veneration was explicitly condemned (1 Kings 11:5, 1 Kings 11:33). Worship of him frequently involved the sacrifice of human children. The word used for “Milcom” could also be translated as “their king.” But this royal title still appears to be referring to a god, which in context is likely Baal (Zephaniah 1:4).
5 those who bow down on the roofs to the host of the heavens, those who bow down and swear to the LORD and yet swear by Milcom,