Tafsir of Sad 38:86

Allah says:

قل ما أسٲلكم عليه من أجر وما أنا من المتكلفين

Say: "No wage do I ask of you for this, nor am I one of the Mutakallifin.'' Allah says: `Say, O Muhammad, to these idolators: I do not ask you to give me any reward from the goods of this world in return for the Message which I convey to you and the sincere advice I offer.'

وما أنا من المتكلفين

nor am I one of the Mutakallifin. means, `and I do not add anything to that which Allah has told me. Whatever I am commanded to do, I do it, and I do not add anything or take anything away. By doing this I am seeking the Face of Allah and the Hereafter.' Sufyan Ath-Thawri, narrated from Al-A`mash and Mansur from Abu Ad-Duha that Masruq said, "We went to `Abdullah bin Mas`ud, may Allah be pleased with him. He said, `O people! Whoever knows a thing should say it, and whoever does not know should say, `Allah knows best.''' It is part of knowledge, when one does not know, to say "Allah knows best.'' For Allah said to your Prophet:

قل ما أسٲلكم عليه من أجر وما أنا من المتكلفين

(Say: "No wage do I ask of you for this, nor am I one of the Mutakallifin.'' This was reported by Al-Bukhari and Muslim

إن هو إﻻ ذكر للعالمين