1 Kings 15:13 - Matthew Poole's English Annotations on the Holy Bible

Her he removed from being queen, i.e. he took from her either the name and authority of queen-regent, which she, having been Rehoboam's wife, and Abijam's mother, took to herself during Asa's minority, and abused to the patronage of idolatry; or the dignity of the queen-mother, and those guards, or other ensigns of honour, or instruments of power, which, as such, she had enjoyed and misemployed. Otherwise, he removed her from the queen, i.e. from his wife, that she might not be infected by her, and afterwards infect his children; which was a prudent and necessary care, for the prevention of so great and public a mischief. An idol, Heb. a terror, or horror, i.e. a horrible idol; which it may be so called, either because all idols, though for a season they please, yet in the end will bring dreadful effects upon their worshippers; or because this was an idol of a more horrible or terrible shape, more abominable than ordinary, and not to be seen without horror; whether it was that filthy idol, called Priapus, which was commonly placed in groves or gardens; or Pan, or some other heathen god, to whose service she in a special manner devoted herself. Burnt it by the brook Kidron; that when it was burnt to powder, it might be thrown into the water, and be unfit for any use. See Exodus 32:20 Deuteronomy 12:3.