Or lest ye should say: "If the Book had only been sent down to us, we should have followed its guidance better than they." Now then hath come unto you a clear (sign) from your Lord,- and a guide and a mercy: then who could do more wrong than one who rejecteth Allah's signs, and turneth away therefrom? In good time shall We requite those who turn away from Our signs, with a dreadful penalty, for their turning away.