وَإِذا لَم تَأتِهِم بِآيَةٍ قالوا لَولَا اجتَبَيتَها ۚ قُل إِنَّما أَتَّبِعُ ما يوحىٰ إِلَيَّ مِن رَبّي ۚ هـٰذا بَصائِرُ مِن رَبِّكُم وَهُدًى وَرَحمَةٌ لِقَومٍ يُؤمِنونَ

And when you, [O Muhammad], do not bring them a sign, they say, "Why have you not contrived it?" Say, "I only follow what is revealed to me from my Lord. This [Qur'an] is enlightenment from your Lord and guidance and mercy for a people who believe."