Dorothy L. Sayers said this quote

If God made everything, did He make the Devil?' This is the kind of embarrassing question which any child can ask before breakfast, and for which no neat and handy formula is provided in the Parents' Manual…Later in life, however, the problem of time and the problem of evil become desperately urgent, and it is useless to tell us to run away and play and that we shall understand when we are older. The world has grown hoary, and the questions are still unanswered.