the holy Quran
sura: Ankaboot verse: 46
Do not argue with the People of the Book(christians and jews) except in a manner which is best, except such of them as are wrongdoers
and say, ‘We believe in what has been sent down to us and in what has been sent down to you; our God and your God is one [and the same] and to Him(Allah) we are submissive