So the sceptic comes along and says "We don't believe in prophecies so they must have been written after the fact and so we'll say in the Babylonian period, and then that proves the gospel comes from the Babylonians and Greeks."
Interesting circular reasoning but that is what sceptic reasoning is.
No, that isn't the reasoning. In fact it has nothing to do with the dating.
While it is widely accepted that the book of Isaiah is rooted in a historic prophet called
Isaiah, who lived in the
Kingdom of Judah during the 8th century BCE, it is also widely accepted that this prophet did not write the entire book of Isaiah.
[9][23]
- Historical situation: Chapters 40–55 presuppose that Jerusalem has already been destroyed (they are not framed as prophecy) and the Babylonian exile is already in effect – they speak from a present in which the Exile is about to end. Chapters 56–66 assume an even later situation, in which the people are already returned to Jerusalem and the rebuilding of the Temple is already under way.[24]
- Anonymity: Isaiah's name suddenly stops being used after chapter 39.[25]
- Style: There is a sudden change in style and theology after chapter 40; numerous key words and phrases found in one section are not found in the other.[26]
The idea that this even refers to a savior is debated. But the OT was revised during the 2nd Temple Period as WorldHistory points out. OT Professor Fransesca S. also speaks on this. So the theology from the Persians and Greeks were added in. The NT is 100% Hellenism and Persian, even copying the Revelation myth exactly.
The Hellenistic World: The World of Alexander the Great
Hellenistic thought is evident in the narratives which make up the books of the Bible as the Hebrew Scriptures were revised and canonized during the Second Temple Period (c.515 BCE-70 CE), the latter part of which was during the
Hellenic Period of the region.
The gospels and epistles of the Christian New Testament were written in Greek and draw on
Greek philosophy and religion as, for example, in the first chapter of the Gospel of John in which the word becomes flesh, a Platonic concept.
Jewish scholars point out that in context the "servant" is clearly not Jesus. They are correct. I'm sure you have corrected people when they used a verse without the full context.
"The broad consensus among Jewish, and even some Christian commentators, that the “servant” in Isaiah 52-53 refers to the nation of Israel is understandable. Isaiah 53, which is the fourth of four renowned Servant Songs, is umbilically connected to its preceding chapters. The “servant” in each of the three previous Servant Songs is plainly and repeatedly identified as the nation of Israel.
Isaiah 41:8-9
But you, Israel, my servant, Jacob, whom I have chosen, the offspring of Abraham, my friend; you whom I took from the ends of the earth, and called from its farthest corners, saying to you, “You are my servant, I have chosen you and not cast you off.”
Isaiah 44:1
But now hear, O Jacob my servant, Israel whom I have chosen!
Isaiah 44:21
Remember these things, O Jacob, and Israel, for you are my servant; I formed you; you are my servant; O Israel, you will not be forgotten by me.
Isaiah 45:4
For the sake of my servant Jacob, and Israel my chosen, I called you by your name, I name you, though you do not know me.
Isaiah 48:20
Go out from Babylon, flee from Chaldea, declare this with a shout of joy, proclaim it, send it out to the end of the earth; say, “The Lord has redeemed his servant Jacob!”
Isaiah 49:3
And he said to me, “You are my servant, Israel, in whom I will be glorified.”
According to this widespread rabbinic opinion, Isaiah 53 contains a deeply moving narrative which world leaders will cry aloud in the messianic age. The humbled kings of nations (52: 15) will confess that Jewish suffering occurred as a direct result of “our own iniquity,” (53:5) e.g., depraved Jew-hatred, rather than, as they previously thought, the stubborn blindness of the Jews."
Who is God's Suffering Servant? The Rabbinic Interpretation of Isaiah 53 | Outreach Judaism