Previous to this, there was the affirmation of prophethood. Now comes the statement which establishes the right of prophethood - it calls for compulsory obedience. In case hostile people refuse to obey, there are words of comfort for the noble Prophet of Islam who has been absolved of any responsibility for their lack of obedience.
The opening statement in the verse presents a very important principle bearing on the authority of the blessed Rasul of Allah. Here, the obedience to the Prophet ﷺ has been equated with obedience to Allah. From this it follows that whoever disobeys the Prophet, invariably disobeys the command of Allah. Since, obedience to Allah is obligatory, even rationally - so, obedience to the Prophet ﷺ also turns out to be equally obligatory. As for the person who, inspite of the truth being all too manifest, elects to turn his back and reject the message given by the Prophet, then, the Prophet has been asked not to worry about the callous behaviour of such people because Allah has not sent His Prophet ﷺ to stand guard over their behaviour for which he is not responsible. It means that the Prophet of Allah is not duty-bound to see that they do not indulge in disbelief. He is simply not charged with the mission of stopping them from disbelieving. His mission is to deliver the Message. Once this is done, his duty as a Prophet stands fulfilled. After that, if they still go about disbelieving, it is their business for which he is in no way accountable. (Maulana Ashraf Thanavi, Bayan al-Qura'n)
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