(Asshuara’) 26 : 109
وَمَا أَسْأَلُكُمْ عَلَيْهِ مِنْ أَجْرٍ ۖ إِنْ أَجْرِيَ إِلَّا عَلَىٰ رَبِّ الْعَالَمِينَ
“And I am not asking you any reward for this; my reward is from none except the Lord of all worlds”.
See explanation 2: 119 and 25: 57.