Scripture famously teaches that, “God is love” (1 John 4:16). But Aquinas thinks this same belief can be shown to be true on the basis of reason alone. If we define love as willing the good of the other for their sake, and if God the First Cause wills the good of human beings for their sake, then God must love human beings. For Thomas whatever God does is also what God is. So if God is loving, then God is love. Moreover, Thomas believes that God so loved the world that Jesus was sent as the fullness of revelation of God. This is a “mystery of faith” that goes beyond what philosophy can show to be true. Thomas thinks that Jesus is fully divine and also fully human. He has both full divine nature and full human nature. 

catholicthinkers.org

https://youtu.be/2wVK0Df3U6E