Have you not read that God uses his angels to pour out his wrath upon the earth? Read Revelation 8, 9, 15, 16. The ungodly will not be his "agents", they will be the objects of his wrath.
Have you not read the Old Testament?
What happened to Samson for his disobedience? What about the Babylonian exile?
What about the holocaust? Was God too weak or scared of Hitler to stop it?
Gods use of the ungodly to judge and discipline His people is a very clear biblical concept.