Andrew Perriman, “‘Before Abraham was, I am’; and before John was the Apocalypse of Abraham” (1.22.24), postost.net.
[I]t is not the historical Jesus who says, “Before Abraham was, I am.” It is a Jesus who emerges out of an engagement with later Jewish-Christian, apocalyptic speculation. John is in critical dialogue with Jews who knew the Apocalypse of Abraham or some associated tradition. Rubinkiewicz says that there is “no direct relationship between the Apocalypse of Abraham and the New Testament” (685), but I think he may be wrong.
This explains what the standard accounts of the text cannot explain, which is why the “I am” claim is connected with Abraham who rejoices and sees Jesus’ day.
Quite what this all means for Johannine christology is hard to say. Is Jesus conceived as the counterpart to the angel who bears the divine name, a powerful agent of divine purpose, perhaps the one eventually sent with the power of God to deliver a people from pagan oppression? Or is closer to the Eternal One, who reveals himself as “I am” to Abraham? In any case, it rather suggests that what we have here is a rhetorical-theological construct rather than a window into the mind of the historical Jesus.
The Amateur Exegete 
From Irenaeus, Against Heresies, Book III, Chapter 11
Since apologists love Irenaeus for his statements about gospel authorship and his closeness to apostle John, I think Irenaeus’ statement that John’s intention in writing the gospel was to refute Cerinthus, establishes a motive on John’s part so partisan and biased that we can reasonably remain suspicious: Indeed, Jesus’ deity is only implicit in the Synoptics, but explicit in John, why? John was trying to refute Cerinthus, who apparently held a lesser view of Jesus. So John caused Jesus to be far more explicit about his divine nature than actual history would allow. Yes, that position commits the skeptic to the position that assertions of Jesus as God are original to the apostle John, but that’s no loss, there was never any reason to attempt proving that Jesus’ deity was a late doctrine. Attributing it to John does more damage to apologists than does trying to prove it is post-apostolic.–Tom
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