Albert Barnes Commentary 2 Kings 22:11

"And it came to pass, when the king had heard the words of the book of the law, that he rent his clothes." — 2 Kings 22:11 (ASV)

He tore his clothes—partly from grief and horror, like Reuben (Genesis 37:29) and Job (Job 1:20), and partly in repentance, like Ahab (1 Kings 21:27).