[3:66] Lo! You are those who dispute about what you know; why do you then dispute concerning that of which you have no knowledge?; and God knows, and you know not.
It means that what was in your Scripture possessed clear evidence and should therefore be a proof for you. He designated either truth or falsehood in that for them. So regarding that for which you have no definitive evidence, or any way of knowing, how can you begin to judge it or make claims to comprehend it?