2 Kings 23:16
And as Josiah turned himself, he spied the sepulchres that were there in the mount, and sent, and took the bones out of the sepulchres, and burned them upon the altar, and polluted it, according to the word of the Lord which the man of God proclaimed, who proclaimed these words.
Cross-reference
2 Kings 23:14
Parallel
In 2 Kings 23:14, Josiah covers sites with human bones to defile them — this same pattern of desecration using bones is applied here to the altar at Bethel.
1 Kings 13:2
Prophetic fulfillment
1 Kings 13:2 contains the precise prophecy that Josiah would burn priests' bones on the altar — he does exactly that.
2 Chronicles 34:5
Parallel
2 Chronicles 34:5 parallels this account, emphasizing that Josiah burned the bones of priests on their altars to purify Judah.