Greatness of the Quran, following the Sunnah and refraining from innovation

[Counselling people :] Beware! what had been ordained has occurred and that which had been destined has come into play. I am speaking to you with the promise and pleas of Allāh. Allāh the Sublime, has said : “Verily, those who say: Our Lord is Allāh! and persevere aright, the angels descend upon them (saying): ‘Fear ye not, nor be grieved, and receive the glad tidings of the Garden which ye were promissed’.” (Qur’ān, 41:30)