Much of historic Christian philosophical theology has affirmed that God not only exists, but is Existence itself. Nowadays, this claim is widely rejected as unintelligible by theists and non-theists alike. I argue in contrast that if there is such a thing as Existence itself, that thing must be a maximally excellent being, which is what many philosophers call God. This is because Existence would itself need to exist, which is only possible if Existence exists in a paradigmatic way, that is, as a perfect instance of existence. My argument thus offers both a defence of the coherence of the claim that God is Existence itself, and a new way of arguing for theism.