Complex sentence: They believe that Maitreya is The Anti-Christ because Maitreya denies that Jesus was the Son of God and claims to embody the the Christ as the New Testament book of the bible says that a man in the New Age would.
Split into simpler sentences: They believe that Maitreya is The Anti-Christ because Maitreya denies that Jesus was the Son of God. He also claims to embody the Christ as the New Testament book of the bible says that a man in the New Age would.