William Lane Craig has expressed concern about Messianic Jews. He says they don't follow the Catholic creeds and see themselves as distinctive. This leaves them open to the "heresies" of the past.
I for one do have a friend who is a Messianic Jew. He does not believe in the Trinity. He is not arian either. He believes in a type of Modelism or Sabellianism.
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2011/11/07 What About Chrislam?