The following is a contribution by Seraphim Hamilton. The original post may be found here.
1. I don’t like talk of a twofold distinction between essence and energies, because it obscures the discussion. The distinction is threefold: person, essence, energies, with the category of person being the unifying principle.
2. Person is who God is, essence is what God is: the content of the person. Energies are what God does: in other words, they are God’s activities. If people simply referred to the energies as the activities (which is what the Greek word means) I feel like all of this would be more intelligible.
3. The activities are of the person. It is the person who acts.
4. St. Maximus asks us to reflect on whether God ever began to do good. His answer is no: God has always been doing good. This is an activity, and the activity is timeless. That’s why we speak of the energies as being eternal. If they are eternal, they are divine.
5. This is the densest part of the doctrine: the activities are the eternal actualizations of the essential (that is, pertaining to the essence) power of deity. Just as your activities reflect who you are, so also the activities of the divine persons reflect who Father, Son, and Spirit are: that is, God.
6. We speak of a distinction between essence and energies in order to preserve the freedom of God. Consider: if essence (what God is) is identical to energy (what God does), then everything that God does is a necessary consequence of what God is. This is why St. Thomas Aquinas was a strict predestinarian and monergist. If, by contrast, the energies are not identical to the essence, then God is free to act in a diverse manner.
7. There are many energies, and they all interpenetrate, but they are still distinct. God’s love is not the same as God’s self-contemplation, even as they are related. This allows us to preserve the plain sense of the biblical God, where He has a range of attributes.
8. We participate in God’s activities through the activity of the Holy Spirit in us. This is what is meant by divinization. St. Paul says (literally) in Colossians: “[I] energize with all the energy that [God] powerfully energizes within me.” The word “energiea” (sp.) is actually a technical term coined by Aristotle and picked up by the Apostle (who was likely trained in philosophy, given his study in Tarsus, which was one of the great centers of philosophical reflection in the ancient world) very deliberately.