He removed the high places, i.e. the most of them, or such as the people most frequented; for all were not taken away, 2 Kings 23:13,14. And this he attempted to do, notwithstanding the people's great and constant affection to them; partly because he had more zeal and courage than his predecessors; and partly because thee dreadful judgments of God upon the kingdom of Israel for their superstition and idolatry had made the people of Judah more pliable to the commands of God, and of their good king. The brazen serpent that Moses had made, by God's command, to be an ordinance or mean for the conveyance of God's blessing to the people; which therefore had been hitherto kept as a memorial of God's mercy; but being now commonly abused to superstition, was destroyed. The children of Israel did burn incense to it; not doubtless as to a god, but only as to an instrument and token of God's mercy, by and through which their adoration was directed to God, and given to that only for God's sake. He called it Nehushtan, i.e. he said, This serpent, howsoever formerly honoured, and used by God as a sign of his grace, yet now it is nothing but a piece of brass, which can do you neither good nor hurt; and therefore is no fit object for your worship.
Related Commentaries of 2 Kings 18:4
2 Kings 18:4
4 He removed the high places, and brake the images,c and cut down the groves, and brake in pieces the brasen serpent that Moses had made: for unto those days the children of Israel did burn incense to it: and he called it Nehushtan.