The truth is that, far from being close to one another in spirit, Judaism and Christianity are almost opposites. Roping them together in the phrase Judeo-Christian is like implying that French revolutionaries and French monarchists had something in common by using the phrase monarcho-republican. An absurd contradiction in terms.
At the heart of Judaism lies the ethnocentric impulse. It is the glorification of a people's obsession with itself. In simple terms, it is racism dressed up as a religion. Christianity, on the other hand, embodies the rejection of the ethnocentric impulse and the embrace of universalism. The break between Christianity and Judaism came when St. Paul rejected the ethnic chauvinism of his fellow Jews and said the message was for the Gentiles too. Indeed, the modern multicultural nightmare we are now living through is really just the long-run consequence of that rejection of ethnocentrism implicit at the dawn of Christianity.
Christianity has come to define Europe, for good and ill, but I can't helping wondering if we would not have been better off had we stuck to the colourful, polytheistic, pagan pantheons like those of the Greeks, Romans, Druids or Nordics, rather than allowing our civilisation to be deformed by the importation of these desert-spawned Oriental cults.
*For Jewish rejection of the concept, see here.
Let’s be clear: Far from “sharing” one tradition, Orthodox Jews are prohibited from marrying Christians, setting foot inside a Christian church—and we can’t even drink from an open bottle of kosher wine that has been used by a Christian. We reject the Christian idea of salvation, we abhor Christian divine teachings on every subject, and we are repulsed and outraged by incessant attempts by Christian missionaries to bring us into their fold.
...Incidentally, we have more in common with Muslims than we do with Christians; Jewish law permits Jews to enter a mosque… but not a church.