How can God exist when the universe seem so cruel and unjust?

My argument against the existence of God was that the universe seemed so cruel and unjust. But how had I got this idea of just and unjust?

A man does not call a line crooked unless he has some idea of a straight line. What was I comparing this universe with when I called it unjust?

As we see, an atheist does not exist – and this is not a joke. In the deepest core of our existential DNA we have the idea of a perfect God which is above all, however no one can know how bad he is in order to search this personal perfection until he has tried very hard to be good or perfect himself.

So, as long as you are proud you cannot know God. A proud man is always looking down on things and people: and, of course, as long as you are looking down you cannot see something that is above you.

Based on C.S. Lewis