Christianity is a monotheistic religion based on the life and oral teachings of Jesus as presented in the New Testament. Christianity is the world's largest religion with approximately 2.2 billion adherents, known as Christians. Most Christians believe that Jesus is the Son of God, fully divine and fully human, and the saviour of humanity whose coming was prophesied in the Old Testament. Consequently, Christians refer to Jesus as Christ or the Messiah.
http://en.wikipedia.org/wiki/Christianity
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