Complex sentence: Abraham (Abraham) does not loom so large in Christianity as he does in Judaism and Islam it is Jesus as the Messiah who is central to Christianity, and the idea of a divine Messiah is what separates Christianity from the other two religions.
Split into simpler sentences: Abraham (Abraham) does not loom so large in Christianity as he does in Judaism and Islam. It is Jesus as the Messiah who is central to Christianity, and the idea of a divine Messiah is what separates Christianity from the other two religions.