Adoptionism, sometimes called dynamic monarchianism, is a minority Christian belief that Jesus was adopted as God's Son either at his baptism, his resurrection, or his ascension. According to Epiphanius's account of the Ebionites, the group believed that Jesus was chosen because of his sinless devotion to the will of God.
Adoptionism was declared heresy at the end of the 2nd century and was rejected by the Synods of Antioch and the First Council of Nicaea, which defined the orthodox doctrine of the Trinity and identified the man Jesus with the eternally begotten Son or Word of God.
Some scholars see Adoptionist concepts in the Gospel of Mark and in the writings of the Apostle Paul. According to this view, though Mark has Jesus as the Son of God, references occurring at the strategic points in 1:1 ("The beginning of the gospel about Jesus Christ, the Son of God", but not in all versions, see Mark 1), 5:7 ("What do you want with me, Jesus, Son of the Most High God?") and 15:39 ("Surely this man was the Son of God!"), the concept of the Virgin Birth of Jesus had not been developed or elucidated at the time of the writing of this early Christian text. By the time the Gospels of Luke and Matthew were written, Jesus is identified as being the Son of God from the time of birth. Finally, the Gospel of John portrays him as the pre-existent Word (Greek: λόγος) as existing "in the beginning".
Early primary writings
Due to recorded predictions of the destruction of the temple, the Gospel of Mark is believed by many critical scholars to have been composed around or shortly after the fall of Jerusalem due to prophecies assumed to be ex post facto regarding the destruction of the temple, and critical scholarly consensus maintains that it was the first written gospel, though the earliest traditional consensus puts Matthew's Gospel as the first of the canonical gospels. The phrase "Son of God" is not present in some early manuscripts at Mark 1:1. Ehrman uses this omission to support the notion that the title "Son of God" is not used of Jesus until his baptism, and that Mark reflects an adoptionist view. The words, "Today I have begotten you," are omitted from the canonical Gospel of Mark, however, and it is therefore generally believed to have less adoptionist tendencies than the Gospel of the Hebrews.
Paul's writings do not explicitly mention a Virgin birth of Christ. Paul wrote that Jesus was "born of a woman, born under the law" and "as to his human nature was a descendant of David" in the Epistle to the Galatians and the Epistle to the Romans. Hebrews 1:5 states that God said, "You are my son. Today I have begotten you," a phrase that shows adoptionist tendencies. It is also almost a direct quote from &src= Psalm 2.
Adoptionism and Christology
Adoptionism is one of two main forms of monarchianism (the other is modalism, which regards "Father" and "Son" as two historical or soteriological roles of a single divine Person). Adoptionism (also known as dynamic monarchianism) denies the eternal pre-existence of Christ, and although it explicitly affirms his deity subsequent to events in his life, many classical trinitarians claim that the doctrine implicitly denies it by denying the constant hypostatic union of the eternal Logos to the human nature of Jesus. Under Adoptionism Jesus is currently divine and has been since his adoption, although he is not equal to the Father, per "my Father is greater than I" (John 14:28). and as such is a kind of subordinationism.
Adoptionism was one position in a long series of Christian disagreements about the precise nature of Christ (see Christology) in the developing dogma of the Trinity, an attempt to explain the relationship between Jesus of Nazareth, both as man and God, and God the Father while confidently claiming to be uncompromisingly monotheistic. It differs significantly from the doctrine of the Trinity that was later affirmed by the ecumenical councils.
Second century: ante-Nicene Christology
The first known exponent of Adoptionism in the 2nd century is Theodotus of Byzantium. According to Hippolytus of Rome (Philosophumena, VII, xxiii) Theodotus taught that Jesus was a man born of a virgin, according to the Council of Jerusalem, that he lived like other men, and was most pious; but that at his baptism in the Jordan the "Christ" came down upon the man Jesus in the likeness of a dove. (Luke 3:22 And the Holy Ghost descended in a bodily shape like a dove upon him, and a voice came from heaven, which said, Thou art my beloved Son; in thee I am well pleased. Luke 4:1 And Jesus being full of the Holy Ghost returned from Jordan, and was led by the Spirit into the wilderness,) Therefore wonders (Greek dynameis) were not wrought in him until the Spirit (which Theodotus called Christ) came down and was manifested in Him. (Philosophumena, VII, xxiii) The belief was declared heretical by Pope Victor I.
The 2nd-century work Shepherd of Hermas also taught that Jesus was a virtuous man filled with the Holy Spirit and adopted as the Son.  While the Shepherd of Hermas was popular and sometimes bound with the canonical scriptures, it didn't retain canonical status, if it ever had it.
In the 3rd century, Paul of Samosata, Patriarch of Antioch, promoted adoptionism. He said Jesus had been a man who kept himself sinless and achieved union with God. His views, however, did not neatly fit in either of the two main forms of Monarchianism.
Medieval and modern Adoptionism
Spanish Adoptionism was a theological position which was articulated in Umayyad and Christian-held regions of the Iberian peninsula in the 8th and 9th centuries. The issue seems to have begun with the claim of archbishop Elipandus of Toledo that – in respect to his human nature – Christ was adoptive Son of God. Another leading advocate of this Christology was Felix of Urgel. In Spain, Adoptionism was opposed by Beatus of Liebana, and in the Carolingian territories, the Adoptionist position was condemned by Pope Hadrian I, Alcuin of York, Agobard, and officially in Carolingian territory by the Council of Frankfurt (794).
Despite the shared name of "Adoptionism" the Spanish Adoptionist Christology appears to have differed sharply from the Adoptionism of early Christianity. Spanish advocates predicated the term adoptivus of Christ only in respect to his humanity; once the divine Son "emptied himself" of divinity and "took the form of a servant" (Philippians 2:7), Christ's human nature was "adopted" as divine.
Historically, many scholars have followed the Adoptionists' Carolingian opponents in labeling Spanish Adoptionism as a minor revival of “Nestorian” Christology. John C. Cavadini has challenged this notion by attempting to take the Spanish Christology in its own Spanish/North African context in his important study, The Last Christology of the West: Adoptionism in Spain and Gaul, 785–820.
12th century and later: Neo-adoptionism
A third wave was the revived form ("Neo-Adoptionism") of Peter Abelard in the 12th century. Later, various modified and qualified adoptionist tenets emerged from some theologians in the 14th century. Duns Scotus (1300) and Durandus of Saint-Pourçain (1320) admit the term Filius adoptivus in a qualified sense. In more recent times the Jesuit Gabriel Vásquez, and the Lutheran divines Georgius Calixtus and Johann Ernst Immanuel Walch, have defended adoptionism as essentially orthodox.
19th century, Psilanthropism
A form of adoptionism surfaced in Unitarianism during the 18th century as the virgin birth was increasingly denied by Unitarians. In the 19th century the term Psilanthropism, was applied by such as Samuel Taylor Coleridge who so called his own view that Jesus was the son of Joseph.
- Epiphanius of Salamis (403 CE). pp. 30:3 & 30:13.
- Harnack, Adolf Von (1889). History of Dogma.
- Edward E. Hindson, Daniel R. Mitchell (2013). The Popular Encyclopedia of Church History: The People, Places, and Events That Shaped Christianity. Harvest House Publishers. p. 23. Retrieved 29 April 2014.
- Witherington, Ben (2006). What Have They Done With Jesus?. San Francisco: Harper Collins. p. 7.
- Ehrman, Bart (1996). The Orthodox Corruption of the Scripture. New York: Oxford University Press. pp. 74–75.
- Crossan, John Dominic (1991). The Historical Jesus. San Francisco: Harper Collins.
- Eisenman, Robert (1998). James the Brother of Jesus. Penguin Books. p. 56.
- Millard, Alan (2000). Reading and writing in the time of Jesus. New York: New York University Press. p. 56.
- Irenaeus (180). Against Heresies. p. 3:1.
- Metzger, Bruce (1996). A Textual Commentary on the Greek New Testament. New York: United Bible Societies. pp. Mark 1:1.
- Justo L. González, Essential Theological Terms, page 139 (Westminster John Knox Press, 2005). ISBN 978-0-664-22810-1
- Ed Hindson, Ergun Caner (editors), The Popular Encyclopedia of Apologetics: Surveying the Evidence for the Truth of Christianity, page 16 (Harvest House Publishers, 2008). ISBN 978-0-7369-2084-1
- "The Holy Pre-existent Spirit. Which created the whole creation, God made to dwell in flesh that he desired. This flesh, therefore, in which the Holy Spirit dwelt, was subject unto the Spirit, walking honorably in holiness and purity, without in any way defiling the Spirit. When then it had lived honorably in chastity, and had labored with the Spirit, and had cooperated with it in everything, behaving itself boldly and bravely, he chose it as a partner with the Holy Spirit; for the career of this flesh pleased [the Lord], seeing that, as possessing the Holy Spirit, it was not defiled upon the earth. He therefore took the son as adviser and the glorious angels also, that this flesh too, having served the Spirit unblamably, might have some place of sojourn, and might not seem to have lost the reward for its service; for all flesh, which is found undefiled and unspotted, wherein the Holy Spirit dwelt, shall receive a reward." 
- "Hermas never mentions Jesus Christ, or the Word, but only the Son of God, who is the highest angel. As holy spirit the Son dwells in the flesh; this human nature is God's adopted son" in, Patrick W. Carey, Joseph T. Lienhard (editors), Biographical Dictionary of Christian Theologians, page 241 (Greenwood Press, 2008). ISBN 0-313-29649-9
- James Ginther, Westminster Handbook to Medieval Theology, (Louisville, KY: Westminster John Knox Press, 2009), 3.
- For an example of this characterization, see Adolph Harnack, ‘’History of Dogma’’, vol. 5, trans. Neil Buchanan, (New York: Dover, 1961), 280.
- John C. Cavadini, ‘’The Last Christology of the West: Adoptionism in Spain and Gaul, 785–820’’, (Philadelphia: University of Pennsylvania Press, 1993), 4–5.
- Cyclopædia of Biblical, theological, and ecclesiastical literature, Volume 2 By John McClintock, James Strong
- Philip Schaff History of the Christian Church, Volume IV, 1882
|Wikisource has the text of the 1911 Encyclopædia Britannica article Adoptianism.|