2 Kings 23:15
Moreover the altar that was at Beth-el, and the high place which Jeroboam the son of Nebat, who made Israel to sin, had made, both that altar and the high place he brake down, and burned the high place, and stamped it small to powder, and burned the grove.
The altar at Bethel and the high place were what Jeroboam the son of Nebat, who made Israel to sin, had made. Josiah broke down both that altar and the high place, burned the high place, and stamped it small to powder. He also burned the grove, the sacred grove at Bethel, and this destruction fulfilled literally the prophecy spoken centuries earlier that a king named Josiah would desecrate and defile that altar.
That prophecy had been spoken long before in the presence of Jeroboam, and the place was profaned as foretold. The altar was polluted as foretold when Josiah turned, saw the sepulchers in the mount, took the bones out of the sepulchers, and burned human bones upon the altar, according to the word of the Lord proclaimed by the man of God from Judah against the altar of Bethel. When told that the marker he saw was the sepulcher of that man of God, Josiah commanded to let him alone and let no man move his bones, so his bones were left alone with the bones of the prophet that came out of Samaria.