Adoptionism is the belief that Jesus was adopted by Son of God, which also seems to presuppose that there is no Trinity. I have heard it argued by Bart Ehrman and other scholars that Adoptionism was a widespread early interpretation of Jesus (which we'd call heresy) in the early-to-mid first century.
Responding to this charge has become relevant in rebutting Muslim proselytizing, which until recent decades had nothing but their (legendary) Hadith for making the claim that Christians corrupted the Bible. Now, "Bart Ehrman! Bart Ehrman! Bart Ehrman!" is the primary content of much Muslim criticism of early Christianity.
I would appreciate some help in responding to these claims.
The major verses cited for this position include Romans 1:3-4 and the version of Luke 3:22 found in the early Western manuscripts of that gospel. Acts 13:33, also written by the author of Luke, and Hebrews 1:5 and 5:5 are also cited.
Here is Romans 1:1-4, from the New American Bible (NAB) translation:
"1 Paul, a slave of Christ Jesus, called to be an apostle and set apart for the gospel of God, 2 which he promised previously through his prophets in the holy scriptures, 3 the gospel about his Son, descended from David according to the flesh, 4 but established as Son of God in power according to the spirit of holiness through resurrection from the dead, Jesus Christ our Lord."
Here is the footnote in the NAB for Luke 3:22:
"You are my beloved Son; with you I am well pleased: this is the best attested reading in the Greek manuscripts. The Western reading, “You are my Son, this day I have begotten you,” is derived from Ps 2:7."
First, regarding Romans 1, these verses are among a very few in the New Testament that are almost universally recognized as representing creeds or hymns about Jesus from before the writings of Paul. Others include Philippians 2:6-11 (notably non-adoptionist in its description of Jesus as having the form of God prior to the Incarnation), 1 Corinthians 15:3-7, 1 Thessalonians 1:3's citation of faith, hope, and love. Though not representing hymns or creeds, I would also throw in Galatians 2:10's concern for the poor by the early church and (possibly, depending on the date of authorship of the rest of that letter) Colossians 1:15-20. I think there is also very good evidence for an early independent tradition of women holding onto the risen Jesus, represented by John 20:17 and Matthew 28:9-10.
The fact that Romans 1:3-4, one of the oldest verses in the New Testament, mentions Jesus as having been "established" (other translations include "appointed") as Son of God is used as grist for the mill by scholars that deny the unity of beliefs within the early Church.
Second, the textual variants of Luke 3:22 are read as evidence that later scribes edited the earliest manuscripts of that Gospel to reflect the orthodoxy of that later time. In particular, Bart Ehrman makes the case that it is more likely that a scribe changed Luke 3:22 to reflect a higher Christology than that a scribe would insert "this day I have begotten you" to make Luke read as having a lower Christology. Acts 13:33 (written by the author of Luke), and Hebrews 1:5 and 5:5 are also cited as evidence.
In general, for these passages, they all refer back to Psalm 2:7. To me, it's not really a big deal that the authors of Luke, Acts, and Hebrews cited the words of the Psalm, which refers to the king being installed on Zion. But much hay is made of the textual variants in Luke 3.
Does anyone have any good (preferably Catholic) references for how to respond?