The phrase “partakers of the divine nature” comes from Peter who says, “His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire” (1 Pet. 1:3-4). This is foundational to participating in the Council of the Lord, which in turn is foundational to the essence of Basileia’s charism. We become partakers of the divine nature via Theosis, but not by our human nature coming into union with God’s divine nature, which happens uniquely only in Jesus where both human nature and divine nature are in unity in His Person. We partake of God’s nature by our human nature coming into union with God’s divine energies, which animate our restored human nature in Christ. This happens in a way where there is no mixture or confusion between God’s energies and our human nature. It is helpful in grasping what divine energies are to contrast these with the divine essence. The essence of God is His transcendent otherness. His energies are His immanent nearness. God's essence is transcendent, unknowable and incommunicable while His uncreated energies are immanent, knowable and communicable. A God of essence only would be a self-enclosed God, unable to communicate outside of Himself. But God is not only essence, He is also energy by which He communicates Himself outside of Himself to His creation. Thus in our partaking of the divine nature, God’s energies and our nature both remain distinct and yet are related just as when an iron poker left in a hot fire takes on all the characteristics of the fire and yet remains distinct from the fire. Glowing red-hot, the poker gives off light and heat just like the fire, but remains what it was before, an iron poker. The poker partakes of the energies of the fire; it does not in its nature become fire. If it is removed from “union” with the fire, it will cease to glow red-hot. In its likeness with the fire, the poker is not the source of the energies that create that likeness but is only a partaker of the energies of the fire. In a similar way, God designed human nature to partake of the divine nature in the sense of absorbing and manifesting His divine energies, not by being blended with His nature. After Moses’ face-to-face encounter with God in His energies, when Moses came down from the mountain, his face shone like the sun.
Also see Council of the Lord, Shine Like the Sun, and Theosis.