The "Early High Christology Club" (i.e., Hengel, Hurtado, Bauckham) have argued that 1. Jewish monotheism was strict, 2. In the first twenty-years of the church some momentous developments happened in christology that resulted in Jesus being identified with the God of Israel and incorporated into patterns of religious devotion normally reserved for YHWH. In contrast, scholars such as James Dunn, Maurice Casey, and James Crossley have argued that we have to wait until the Gospel of John (e.g., 1.1, 8.58) before we encounter any christological beliefs in Jesus' identity that genuinely transgresses what was acceptable in the first century Jewish monotheism . However, some are now contesting whether Johannine christology (from the Gospel and Revelation) really go so far as to include Jesus within the identity of God, or simply place Jesus in an exalted and divine state beside God. I've already noted the arguments of A.Y. Collins that the Johannine materials present Jesus as the most eminent created being (was Arius right afterall?). Now James McGrath in his book The Only True God: Early Christian Monotheism in Its Jewish Context, contents that:
1. In the Fourth Gospel - "The claim that Jesus was the Messiah, God's supreme agent, was clearly a sticking oint between Christians and non-Christian Jews, and the group whose traditions and experiences are reflected in the Gospel of John are no exception. However, it seems that it was not the things that were said that were in themselves provocative and controversial in the abstract. Rahter, what was really at issue was the fact taht these things were said about Jesus. Similar language applied to an even, or even to a huan being was was universally accepted within Judaism as having been divinely appointed and sent, did not provoke this sort of controversy. This simple fact makes clear that what was at issue was not hte idea of the Logos, nor the idea of a divine agent bearing the divine name, but the claim that Jesus was such a figure" (pp. 68-69).
2. In Revelation: "The inclusion of God's appointed representative alongside God as recipient of praise is noteworthy, but it is neither unique nor without precedent. Such a development was foreseen to a certaiin extent and was perhaps even to be expected as a response to the appearance of God's agent in the realization of his eschatological salvation ... And so the depiction of Christ in the Book of Revelation represents a development within the context of Jewish monotheism rather than a development away from Jewish devotion to the only one God" (p. 76).
Several criticims could be made here (James McGrath and Michael Whitenton had an exchange over this I believe) and I'll leave it to others to examine McGrath's points.