Al-Furqaan 57

قُلْ مَآ أَسْـَٔلُكُمْ عَلَيْهِ مِنْ أَجْرٍ إِلَّا مَن شَآءَ أَن يَتَّخِذَ إِلَىٰ رَبِّهِۦ سَبِيلًا ﴿٥٧﴾

Qul ma asalukum AAalayhi min ajrin illa man shaa an yattakhitha ila rabbihi sabeelan

Say: "No reward do I ask of you for this (that which I have brought from my Lord and its preaching, etc.), save that whosoever wills, may take a Path to his Lord. The Noble Quran