The Mohammedans have already declared our scriptures false.
Not entirely ... they accept some aspects as being true, but accuse us of falsifying parts. The Mohammedans accept most of the major characters in the Scriptures from Ibrahim to Issa ... but the mohammedan understanding of them is wildly inconsistent with ours. So much so as to be largely contradictory. Logically, we could be right. Or the mohammedans could be right. Or we and the mohammedans could both be wrong. But we and the mohammedans CANNOT both be right.