And when he was in distress he entreated Yahweh his God and greatly humbled himself before the God of his ancestors and prayed to him. And God responded to him and heard his plea and let him return to Jerusalem to his kingdom. And Manasseh knew that Yahweh was God.” (2 Chronicles 33:12–13, LEB)

Manasseh made a hash of being king.  The Bible says”“And Manasseh seduced Judah and the inhabitants of Jerusalem to do evil more than the nations that Yahweh destroyed before the Israelites.” (2 Chronicles 33:9, LEB)  His guilt was very great because he was the leader of God’s people and he led the people into very great sin.

That, however, is not the end of the story.  He got taken prisoner by the king of Assyria and sent to Babylon, a very long way away.  There he was in great distress and there he was in captivity.  Then vs. 12: And when he was in great distress he entreated Yahweh his God and greatly humbled himself…

And God forgave him, and also restored him.  This is a beautiful picture of undeserved grace which will be shown perfectly at the cross.  In reality we are all Manasseh.  The Bible says that “we have turned every one to his own way and the Lord has laid on him the iniquity of us all.” (Is. 53.6)  Fortunately for us, we follow the same God that Manasseh followed and his grace is the same as ever.  When we greatly humble ourselves, when we repent of our sins, his grace is extended in the same manner as Manasseh received it.