Judeo-Christian: Term grouping Judaism and Christianity together

The Old Testament, which is the first half of the Christian bible is based on the 24 books of the Hebrew Bible. Since about the 19th century, the term Judeo-Christian is used, to either describe this common heritage, or to show how Christianity developed from Judaism. The term Abrahamic religions also includes other religions, for which Abraham was an important person, most notably Islam.

At the time of Christ, Judaism was legal within the Roman Empire, and Jews were permitted to worship their religion. Christians were not covered by this arrangement, yet they had in the first century A.D. no Bible: the first book of the New Testament was not written until about 100 AD, though even that date this is not precisely known. It is deduced from its internal content. The other books were written even later. That is why in modern Bibles over half the content is from the Jewish tradition.

The words 'Judæo Christian' first appeared in the 19th century as a word for Jewish converts to Christianity. Some Jewish writers objected, because they felt it was used to pretend there were no important differences between the two religions. It was used a lot in America during the Cold War, to show that the country was united against communist atheism. It is still used sometimes in discussions about Western values and against Islam.