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Early Christian Deification Belief
Early Church Belief in Deification
The LDS church believes that all mankind are literal sons and daughters of God the Father, and that we can progress and learn and eventually become like God. This idea is called "deification". Understand that official doctrine does not specify if this means we can become a god with a big "G" (like our Father in Heaven), or a little "g" (like Thor). However, the basic concept is doctrinal. The idea was blasphemous to Catholics and Protestants of Joseph Smith's day. But did Early Christians believe this?
What scriptures support deification?
I have said, Ye are gods; and all of you are children of the most High. Psalms 82:6
...we are the offspring of God Acts 17:28
Beloved, now are we the sons of God...when he shall appear, we shall be like him...1 John 3:2
...The Spirit itself beareth witness with our spirit, that we are the children of God: And if children, then heirs; heirs of God, and joint-heirs with Christ...Romans 8:16-17
Early Christian Belief in Deification
Irenaeus (ca. AD 115-202)
Saint Irenaeus, who may justly be called the first Biblical theologian among the ancient Christians, was a disciple of the great Polycarp, who was a direct disciple of John the Revelator.  Irenaeus is not a heretic or unorthodox in traditional Christian circles, yet he shares a belief in theosis:
While man gradually advances and mounts towards perfection; that is, he approaches the eternal. The eternal is perfect; and this is God. Man has first to come into being, then to progress, and by progressing come to manhood, and having reached manhood to increase, and thus increasing to persevere, and persevering to be glorified, and thus see his Lord. 
Like the LDS, Irenaeus did not believe that this belief in any way displaced God, Christ, or the Holy Ghost:
there is none other called God by the Scriptures except the Father of all, and the Son, and those who possess the adoption....Since, therefore, this is sure and stedfast, that no other God or Lord was announced by the Spirit, except Him who, as God, rules over all, together with His Word, and those who receive the Spirit of adoption. 
Yet, Irenaeus—whom it would be perverse to exclude from the ranks of orthodox Christians—believed in theosis in terms which agree with LDS thinking on the matter:
We were not made gods at our beginning, but first we were made men, then, in the end, gods. 
How then will any be a god, if he has not first been made a man? How can any be perfect when he has only lately been made man? How immortal, if he has not in his mortal nature obeyed his maker? For one's duty is first to observe the discipline of man and thereafter to share in the glory of God. 
Our Lord Jesus Christ, the Word of God, of his boundless love, became what we are that he might make us what he himself is.” 
But of what gods [does he speak]? [Of those] to whom He says, "I have said, Ye are gods, and all sons of the Most High." To those, no doubt, who have received the grace of the "adoption, by which we cry, Abba Father."” 
And, Irenaeus considers the doctrine clearly Biblical, just as the LDS do:
For he who holds, without pride and boasting, the true glory (opinion) regarding created things and the Creator, who is the Almighty God of all, and who has granted existence to all; [such an one, ] continuing in His love and subjection, and giving of thanks, shall also receive from Him the greater glory of promotion, looking forward to the time when he shall become like Him who died for him, for He, too, "was made in the likeness of sinful flesh," to condemn sin, and to cast it, as now a condemned thing, away beyond the flesh, but that He might call man forth into His own likeness, assigning him as [His own] imitator to God, and imposing on him His Father's law, in order that he may see God, and granting him power to receive the Father; [being] the Word of God who dwelt in man, and became the Son of man, that He might accustom man to receive God, and God to dwell in man, according to the good pleasure of the Father. 
Said one Protestant theologian of Irenaeus:
Participation in God was carried so far by Irenaeus as to amount to deification. 'We were not made gods in the beginning,' he says, 'but at first men, then at length gods.' This is not to be understood as mere rhetorical exaggeration on Irenaeus' part. He meant the statement to be taken literally. 
Clement of Alexandria (AD 150-215)
Clement, an early Christian leader in Alexandria, also taught the doctrine of deification:
yea, I say, the Word of God became a man so that you might learn from a man how to become a god. 
...if one knows himself, he will know God, and knowing God will become like God...His is beauty, true beauty, for it is God, and that man becomes god, since God wills it. So Heraclitus was right when he said, "Men are gods, and gods are men." 
Those who have been perfected are given their reward and their honors. They have done with their purification, they have done with the rest of their service, though it be a holy service, with the holy; now they become pure in heart, and because of their close intimacy with the Lord there awaits them a restoration to eternal contemplation; and they have received the title of "gods" since they are destined to be enthroned with the other "gods" who are ranked next below the savior. 
Origen (ca. AD 185-251)
And thus the first-born of all creation, who is the first to be with God, and to attract to Himself divinity, is a being of more exalted rank than the other gods beside Him, of whom God is the God, as it is written, "The God of gods, the Lord, hath spoken and called the earth." It was by the offices of the first-born that they became gods, for He drew from God in generous measure that they should be made gods, and He communicated it to them according to His own bounty. The true God, then, is "The God," and those who are formed after Him are gods, images, as it were, of Him the prototype. 
The Father, then, is proclaimed as the one true God; but besides the true God are many who become gods by participating in God. </ref>Origen in Bettensen, Henry. The Early Christian Fathers, 324.</ref>
Origen also defined what it means to "participate" in something:
Every one who participates in anything, is unquestionably of one essence and nature with him who is partaker of the same thing. 
Justin Martyr (d. ca. AD 163)
Justin the Martyr said in 150 A.D. that he wishes
to prove to you that the Holy Ghost reproaches men because they were made like God, free from suffering and death, provided that they kept His commandments, and were deemed deserving of the name of His sons... in the beginning men were made like God, free from suffering and death, and that they are thus deemed worthy of becoming gods and of having power to become sons of the highest... 
[By Psalm 82] it is demonstrated that all men are deemed worthy of becoming “gods,” and even of having power to become sons of the Highest. 
Hippolytus (AD 170-236)
Now in all these acts He offered up, as the first-fruits, His own manhood, in order that thou, when thou art in tribulation, mayest not be disheartened, but, confessing thyself to be a man (of like nature with the Redeemer,) mayest dwell in expectation of also receiving what the Father has granted unto this Son...The Deity (by condescension) does not diminish anything of the dignity of His divine perfection having made you even God unto his glory. 
In 347, Athanasius, Bishop of Alexandria and participant in the council of Nicea, said:
the Word was made flesh in order that we might be enabled to be made gods....just as the Lord, putting on the body, became a man, so also we men are both deified through His flesh, and henceforth inherit everlasting life...[we are] sons and gods by reason of the word in us. 
For as Christ died and was exalted as man, so, as man, is He said to take what, as God, He ever had, that even such a grant of grace might reach to us. For the Word was not impaired in receiving a body, that He should seek to receive a grace, but rather He deified that which He put on, and more than that, gave it graciously to the race of man. 
He also states that Christ "became man that we might be made divine." 
Augustine (AD 354-430)
Augustine, considered one of the greatest Christian Fathers, said
but He himself that justifies also deifies, for by justifying He makes sons of God. For He has given them power to become the sons of God, (John 1:12). If then we have been made sons of God, we have also been made gods. 
Jerome (AD 340-420)
Jerome also described the deification of believers as an act of grace, which matches the LDS understanding precisely:
“I said 'you are gods, all of you sons of the most high.’" let Eunomius hear this, let Arius, who say that the son of God is son in the same way we are. That we are gods is not so by nature, but by grace. “but to as many as receive Him he gave power to becoming sons of God” I made man for that purpose, that from men they may become gods. We are called gods and sons!...[Christ said] "all of you sons of the Most High," it is not possible to be the son of the Most High, unless He Himself is the Most High. I said that all of you would be exalted as I am exalted. 
Jerome goes on to say that we should
give thanks to the God of gods. The prophet is referring to those gods of whom it is written: I said ‘you are gods’ and again ‘god arises in the divine assembly’ they who cease to be mere men, abandon the ways of vice an are become perfect, are gods and the sons of the most high... 
Modern Christian exegesis
The Westminster Dictionary of Christian Theology describes "deification" thusly:
Deification (Greek Theosis) is for orthodoxy the goal of every Christian. Man, according to the Bible, is ‘made in the image and likeness of God’...it is possible for man to become like God, to become deified, to become God by grace. This doctrine is based on many passages of both O.T. and N.T. (Psalms 82: (81) .6; 2 Peter 1:4), and it is essentially the teaching both of St. Paul, though he tends to use the language of filial adoption (Romans 8:9-17, Galatians 4:5-7) and the fourth gospel (John 17:21-23). 
Joseph Fitzmyer wrote:
The language of 2 Peter is taken up by St. Irenaeus, in his famous phrase, ‘if the Word has been made man, it is so that men may be made gods; (adv. Haer v, pref.), And becomes the standard in Greek theology. In the fourth century St. Athanasius repeats Irenaeus almost word for word, and in the fifth century St. Cyril of Alexandria says that we shall become sons ‘by participation’ (Greek methexis). Deification is the central idea in the spirituality of St. Maximus the confessor, for whom the doctrine is corollary of the incarnation: ‘deification, briefly, is the encompassing and fulfillment of all times and ages’,...and St. Symeon the new theologian at the end of the tenth century writes, ‘he who is God by nature converses with those whom he has made gods by grace, as a friend converses with his friends, face to face...’
Finally, it should be noted that deification does not mean absorption into God, since the deified creature remains itself and distinct. It is the whole human being, body and soul, who is transfigured in the spirit into the likeness of the divine nature, and deification is the goal of every Christian. 
According to Christian scholar G.L. Prestige, the ancient Christians “taught that the destiny of man was to become like God, and even to become deified.” 
William R. Inge, Archbishop of Canterbury, wrote:
"God became man, that we might become God" was a commonplace of doctrinal theology at least until the time of Augustine, and that "deification holds a very large place in the writings of the fathers...We find it in Irenaeus as well as in Clement, in Athanasius as well in Gregory of Nysee. St. Augustine was no more afraid of deificari in Latin than Origen of apotheosis in Greek...To modern ears the word deification sounds not only strange but arrogant and shocking. 
The Eastern Orthodox Church broke off and became their own sect over the doctrine of deification or "theosis", and believe the same today.
Yes, these "arrogant and shocking" doctrines were clearly held by early Christians!
This view of the early Christians' doctrines is not unique to the Latter-day Saints. Many modern Christian writers have recognized the same doctrines. If some modern Christians do not wish to embrace these ancient doctrines, that is their privilege, but they cannot logically claim that such doctrines are not "Christian." One might fairly ask why modern Christians do not believe that which the ancient Christians insisted upon?
- Template:ECF1; Citing Irenaeus, Against Heresies, 4.38 cp. 4.11.
- Arthur C. McGiffert, A History of Christian Thought, Vol. 1—Early and Eastern: From Jesus to John of Damascus (New York: Scribner's Sons, 1932), 141.
- Clement of Alexandria, Exhortation to the Greeks, 1. off-site
- Clement of Alexandria, The Instructor, 3.1 see also Clement, Stromateis, 23.Template:NeedCite
- Template:ECF; Stromata 7:10 (55–56).
- Origen, Commentary on John, Book II, Chapter 2.
- Origin, De Principiis, 4:1:36 in Ante-Nicene Fathers 4:381.
- Justin Martyr, Dialogue with Trypho, 124.
- Justin Martyr, Dialogue with Trypho, 124.
- Hippolytus, Refutation of All Heresies 10:29-30, in Ante-Nicene Fathers 5:152.
- Athanasius, Against the Arians, 1.39, 3.39.
- Athanasius, Against the Arians, 1:42, in Nicene and Post-Nicene Fathers, Second Series, 4:330-331.
- Athanasius, On the Incarnation, 54.
- Augustine, On the Psalms, 50:2.
- Jerome, The Homilies of Saint Jerome, 106–107.
- Jerome, The Homilies of Saint Jerome, 106–353.
- Alan Richardson (editor), The Westminster Dictionary of Christian Theology (Westminster: John Knox Press, 1983). ISBN 0664213987. (emphasis added).
- Joseph A. Fitzmyer, Pauline Theology: a brief sketch (Prentice-Hall, 1967), 42. AISN B0006BQTCQ.
- G.L. Prestige, God in Patristic Thought (London Press, 1956), 73.
- William Ralph Inge, Christian Mysticism (London, Metheun & Co., 1948), 13, 356.