Partakers of the divine nature
'Partakers of the divine nature' — transformation into God (theosis) in Orthodox reading, moral likeness, or an eschatological promise (with 2 Corinthians 3:18).
2 Peter 1:3-4
3seeing that his divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us by his own glory and virtue,
4by which he has granted to us his precious and exceedingly great promises; that through these you may become partakers of the divine nature, having escaped from the corruption that is in the world by lust.
What each tradition says
Rabbinic / Midrashic
Rabbi Akiva taught that man is beloved because he was created in God’s image. He is especially beloved because it was made known to him that he was created in God’s image, as it is said, “for in the image of God He made man” (Genesis 9:6).
Rabbi Akiva (mishnah, Pirkei Avot 3:14); English: Dr. Joshua Kulp (Mishnah Yomit, Sefaria), Pirkei Avot (Mishnah, c. 200 CE); Sefaria's Mishnah Yomit translation — Pirkei Avot 3:14 (R. Akiva on the divine image)
Patristic
Athanasius says He was made man so that we might be made God. He manifested Himself by a body so we might receive the idea of the unseen Father, and He endured the insolence of men so we might inherit immortality.
Athanasius of Alexandria (c. 296-373), On the Incarnation of the Word (trans. Archibald Robertson), in Nicene and Post-Nicene Fathers, ser. 2, vol. 4 (eds. Philip Schaff and Henry Wace; New York: Christian Literature Publishing Co., 1892) — ch. 54, section 3 (the concluding summary of the benefits of the Incarnation)
Catholic
Thomas Scannell holds that 2 Peter 1:4's "partakers of the divine nature" should be taken as literally as possible. This does not mean generation from God's substance, but a communication of divine life by God's power and a most intimate indwelling of His substance in the creature.
Thomas Scannell, The Catholic Encyclopedia, vol. 6, s.v. 'Supernatural Gift' (New York: Robert Appleton Company, 1909) — Section on divine adoption (citing 2 Peter 1:4)
Orthodox
Basil of Caesarea lists foreknowledge of the future, understanding of mysteries, apprehension of what is hidden, distribution of good gifts, heavenly citizenship, a place in the chorus of angels, joy without end, abiding in God, and being made like to God. Highest of all, he says, is being made God.
Basil of Caesarea (c. 330-379), On the Holy Spirit (trans. Blomfield Jackson), in Nicene and Post-Nicene Fathers, ser. 2, vol. 8 (eds. Philip Schaff and Henry Wace; Edinburgh: T&T Clark, 1895) — ch. 9, section 23 (the gifts wrought in the soul by the Spirit)
Reformed / Protestant
Calvin marks that the end of the gospel is to render us eventually conformable to God and, if he may so speak, to deify us. He clarifies that the word nature here is not essence but quality.
John Calvin (1509-1564), Commentaries on the Catholic Epistles (trans. John Owen; Edinburgh: Calvin Translation Society, 1855) — Commentary on 2 Peter 1:4 (within the comment on 2 Peter 1:1-4)
Evangelical
John Wesley writes that ye may become partakers of the divine nature. This is by being renewed in the image of God and having communion with them, so as to dwell in God and God in you.
John Wesley (1703-1791), Explanatory Notes upon the New Testament (1755); CCEL's 'Wesley's Notes on the Bible' — Note on 2 Peter 1:4