You believe in the holy trinity and Islam only in God, which Christianity calls the father but this issue has been raised in public debates the conclusion of these arguments have always been unverified with credible or tangible evidence because we are not dead yet neither is the day of judgement upon us. so knowing, which side is speaking the truth is impossible. so arguing is not going to give you any satisfaction so I would say let it be. you would believe that Christianity came after Judaism. so this is a social experiment conducted in Isreal to see which of the religions are closer to Judaism.