There are all sorts of different reasons for believing in God, and here I will mention only one. It is this.
Supposing there was no intelligence behind the universe, no creative mind. In that case nobody designed my brain for the purpose of thinking. It is merely that when the atoms inside my skull happen for physical or chemical reasons to arrange themselves in a certain way, this gives me as a by-product, the sensation I call thought.
But if so, how can I trust my own thinking to be true? It is like upsetting a milk-jug and hoping that the way the splash arranges itself will give you a map of London. But if I cannot trust my own thinking, of course I cannot trust the arguments leading to
atheism and therefore the reason to be an atheist, or anything else.
Unless I believe in God, I cannot believe in thought or anything else: so I can never use thought to disbelieve in God.
C. S. Lewis