Gottfried Wilhelm Leibniz

Now this sufficient reason of the existence of the universe cannot be found in the sequence of contingent things … Thus the sufficient reason, which has no need of any other reason, must needs be outside of this sequence of contingent things and must be in a substance which is the cause of this sequence, or which is a necessary being, bearing in itself the reason of its own existence, otherwise we should not yet have a sufficient reason with which we could stop. And this ultimate reason of things is called God.