the sufficiency of the Qur'an

إِنَّ فِى هَـٰذَا لَبَلَـٰغًا لِّقَوْمٍ عَـٰبِدِينَ

Indeed, in this [Qur’ān] is notification for a worshipping people.

لَوْ أَنَّ عِندَنَا ذِكْرًا مِّنَ ٱلْأَوَّلِينَ

"If we had a message from [those of] the former peoples,