EWTN Catholic Q&A
All Knowing God
Question from Larry Bradshaw on 04-27-2017:

Please help my keeping the faith. God is All-Knowing. Did He know that by creating the Angel of Light, Lucifer, that He would become the devil? Why did He go ahead and create Lucifer?

Answer by Richard Geraghty on 04-27-2017:

Dear Larry,

Only God know what he should do. We creatures cannot be the judges.

De. Geraghty