You brought this upon yourself with your example, which roughly meant that only knowing enough about 2nd temple Judaism could grant you a say in these matters. People here are more or less just probing you about what is actually known about this, and as it turns out, not so much.
No that's not exactly true. We can't be absolutely certain about when or how the messianic concept entered into Jewish life. But there is evidence that the familiar concept of THE messiah = a secular monarch/military strongman existed in the DSS. Given that people writing in the early to mid second century identify this as an extremely familiar Jewish concept, one that requires very little in the way of exegesis or explanation it is safe to assume that THE messiah was known to the gospel writer and the Marcionite claim that he distinguished Jesus from that concept likely dates to the first century.
The idea that the gospel author lived in an environment which didn't know the Jewish messianic concept is extremely unlikely which leaves us - given Jesus's obvious estrangement from that ideal in terms of how he was portrayed - with only one possibility, Jesus represents something else from the Jewish 'cupboard' of religious ideas.
As I said somewhere in the middle of this thread, given that the original 'mythical' or 'supernatural' gospel narrative has Jesus floating down from heaven to a Jewish house of worship declaring that is 'the year of favor' it is impossible that any other cultural context could be at work here. The gospel might have been written by a Samaritan, a Jew, a Jewish proselyte or some other sectarian background that bridged those aforementioned categories but this was not written by a Gentile or written for another audience or culture.
Moreover when Peter announces that Jesus is the Christ, Clement of Alexandria points out that the gospel has Jesus correct Peter to recognize him as a divine being. Once again, the familiar Jewish concept was known to the gospel writer and here - as with a number of other occasions (i.e. the blind man in Jericho who at first announces Jesus as 'the son of David' but then has his eyes open and then calls him 'the Lord' according to Marcionite exegesis etc) the familiar messianic concept is being actively rejected in favor of identify Jesus with a god, the very god who gave the ten commandments to Moses.
I make 'absolute' statements about the Jewish origins for the gospel and the theology of Paul because there is no other reasonable alternative. Mithras did not announce the ten commandments. Osiris did not have a year of favor which commenced in the seventh month of the Jewish calendar. The concept of 'gospel' was not connected with any pagan religious setting. The only answer time and time again is that the gospel was written for an exclusively Jewish audience as it references only Jewish theological themes.
