Disinterestedness in Da'wah (Islamic Preaching)

يَـٰقَوْمِ لَآ أَسْـَٔلُكُمْ عَلَيْهِ أَجْرًا ۖ إِنْ أَجْرِىَ إِلَّا عَلَى ٱلَّذِى فَطَرَنِىٓ ۚ أَفَلَا تَعْقِلُونَ

O my people, I do not ask you for it [i.e., my advice] any reward. My reward is only from the one who created me. Then will you not reason?