Summa Theologica

This is what is ultimate in our human knowledge of God, to know that we do not know. Our great tragedy is that we know too much. We think we know, that is our tragedy; so we never discover. In fact, Thomas Aquinas (he’s not only a theologian but also a great philosopher) says repeatedly, “All the efforts of the human mind cannot exhaust the essence

“The divine substance surpasses every form that our intellect reaches,” announced Thomas Aquinas in the philosophical argot of his time. And he drew the personal consequences: “He knows God best who acknowledges that whatever he thinks or says falls short of what God really is”

Accordingly, if the divine essence is distinct from its existence, it follows that His essence and existence are mutually related as potentiality and act. Now it has been proved that in God there is nothing of potentiality, and that He is pure act. Therefore God’s essence is not distinct from His existence.