The impression I get from the New Testament is that the idea of Jesus dying for anybody is primarily Hellenistic, if not strictly Gentile. It is particularly central to Paul -- who does have some connection with Judaism but mostly addresses Gentiles. The very point of "justification through faith in Jesus, not by the works of the Law" is to provide an alternative way of salvation for Gentiles. Of course the idea eventually crept into Jewish "Christianity" but when it was not completely rejected it never became essential to it. For instance, the mostly Jewish-Christian Matthew (20:28) keeps the idea of "ransom" from the Hellenistic and Gentile-friendly Mark (10:45) but it remains rather disconnected from the rest of the Matthean Gospel which (as the previous discussion on this thread shows) emphasises salvation by action and radical (though non-conformist) observance of the Law.