What I said is: evil is not an idea. It is an action (spiritually or physically).
When you "think" evil, you are not thinking about the evil itself. You are thinking about something like murder, stealing, etc. God does not tell you to do (or to think about) those things. You want to do them because you have the free will.
Think about the story of Abel and Cain. When Cain feels that he wants to kill, is he thinking about evil? No. he is thinking about justice. God did not tell Cain that he should not kill (Abel was "killing" his sheep all the time). Before God blames Cain, there was no evil involved in the whole incidence. Of course God knows what is killing. But before God says: thou should not kill, killing is not evil
What I am saying is: your question is not a valid one. You can not say that God has the "evil" thought of killing at the first place.