Albert Barnes Commentary 2 Kings 21:16

"Moreover Manasseh shed innocent blood very much, till he had filled Jerusalem from one end to another; besides his sin wherewith he made Judah to sin, in doing that which was evil in the sight of Jehovah." — 2 Kings 21:16 (ASV)

Compare to Jeremiah 2:30, Hebrews 11:37, and Isaiah 57:1-4. According to tradition, Isaiah was among the first to perish. More than a century afterward, the final judgment upon Jerusalem was felt to be, in a special way, the punishment for Manasseh’s bloody persecution of God’s people (see the marginal reference).