What are some important primary sources on Jewish influence upon early Christianity?
Depending on how early you mean, there is very little mention of Christianity outside Christian texts - Pliny the Younger and Taticus are the only two I know of. I'd turn to early Christian apologists such as Justin Martyr for other tidbits of information.
I am looking for 300 BCE to 300 AD. Those two are very good. I am working through them at this point. Christianity began with Jewish eschatological expectations and evolved into the veneration of Jesus as a result of his earthly ministry. Any further primary sources are greatly helpful.
NT Wright’s New Testament and the People of God (https://www.logos.com/product/8778/the-new-testament-and-the-people-of-god) does this very comprehensively, tracing the nature of Jewish monotheism back into the inter-testamental period , covering the nature of Seconf Temple Judaism and the various groups in Judaea at the time of Jesus. Not a primary text, but the footnotes give you the relevant primary texts.
I'm having a serious problem with all your threads on this topic. The original Christians at the time of Pentecost were Jews not Christians influenced by Judaism. Are you asking:
And yes, although I can't remember the title, I have seen a book by a rabbi denying the Jewish origin of Christianity.
It seems to me that some secondary literature may actually be better at covering your topic:
Unity and Diversity in the New Testament: An Inquiry into the Character of Earliest Christianity by James D.G. Dunn
When Christians Were Jews: The First Generation by Paula Fredriksen
I am looking to answer all these questions below
And these questions as well.