الَّذِينَ كَذَّبُوا بِالْكِتَابِ وَبِمَا أَرْسَلْنَا بِهِ رُسُلَنَا ۖ فَسَوْفَ يَعْلَمُونَ (70)
(40:70) Those who gave the lie to this Book and all the Books which We had sent with Our Messengers *100 shall soon come to know the Truth
*100) This is the real cause of their going astray Their denial of the Qur'an and the teachings brought by the Messenger of AIlah and their resisting by disputation the Revelations of Allah instead of pondering over them seriously, was the basic cause, which has led them astray and exhausted all possibilities of their adopting the Right Way .