In God's opinion he was a bad king - an evil king. He reintroduced all the moral rot and spiritual corruption that had been scoured from the country when God dispossessed the pagan nations in favor of the children of Israel.
He rebuilt the sex-and-religion shrines that his father Hezekiah had torn down, he built altars and phallic images for the sex god Baal and the sex goddess Asherah and worshiped the cosmic powers, taking orders from the constellations.
He built shrines to the cosmic powers and placed them in both courtyards of The Temple of God,
the very Jerusalem Temple dedicated exclusively by God's decree to God's Name ("in Jerusalem I place my Name").
He burned his own sons in a sacrificial rite in the Valley of Ben Hinnom. He practiced witchcraft and fortunetelling. He held sŽances and consulted spirits from the underworld. Much evil - in God's view a career in evil. And God was angry.
As a last straw he placed a carved image of the sex goddess Asherah that he had commissioned in The Temple of God, a flagrant and provocative violation of God's well-known command to both David and Solomon, "In this Temple and in this city Jerusalem, my choice out of all the tribes of Israel, I place my Name - exclusively and forever."
He had promised, "Never again will I let my people Israel wander off from this land I've given to their ancestors. But on this condition, that they keep everything I've commanded in the instructions my servant Moses passed on to them."
But Manasseh led Judah and the citizens of Jerusalem off the beaten path into practices of evil exceeding even the evil of the pagan nations that God had earlier destroyed.
When God spoke to Manasseh and his people about this, they ignored him.
Then God directed the leaders of the troops of the king of Assyria to come after Manasseh. They put a hook in his nose, shackles on his feet, and took him off to Babylon.
Now that he was in trouble, he went to his knees in prayer asking for help - total repentance before the God of his ancestors.