Dalil

Quran Sad 38:86

قُلۡ مَآ أَسۡـَٔلُكُمۡ عَلَيۡهِ مِنۡ أَجۡرٖ وَمَآ أَنَا۠ مِنَ ٱلۡمُتَكَلِّفِينَ

Translation

Say, [O Muḥammad], "I do not ask you for it [i.e., the Qur’ān] any payment, and I am not of the pretentious.