وَمَا مُحَمَّدٌ إِلَّا رَسُولٌ قَدْ خَلَتْ مِن قَبْلِهِ ٱلرُّسُلُ ۚ أَفَإِي۟ن مَّاتَ أَوْ قُتِلَ ٱنقَلَبْتُمْ عَلَىٰٓ أَعْقَـٰبِكُمْ ۚ وَمَن يَنقَلِبْ عَلَىٰ عَقِبَيْهِ فَلَن يَضُرَّ ٱللَّهَ شَيْـًٔا ۗ وَسَيَجْزِى ٱللَّهُ ٱلشَّـٰكِرِينَ
Asad Quran Translation
AND MUHAMMAD is only an apostle; all the [other apostles have passed away before him: if, then, he die or is slain, will you turn about on your heels?104
But he that turns about on his heels can in no wise harm God - whereas God will requite all who are grateful [to Him].
This stress on the mortality of the Prophet - and that of all the other prophets who preceded him in time - connects, in the first instance, with the battle of Uhud and the rumour of his death, which caused many Muslims to abandon the fight and even brought some of them close to apostasy (Tabari; see also note  above). In its wider implication, however, the above verse re-states the fundamental Islamic doctrine that adoration is due to God alone, and that no human being - not even a prophet - may have any share in it. It was this very passage of the Qur'an which Abu Bakr, the first Caliph, recited immediately after the Prophet's death, when many faint-hearted Muslims thought that Islam itself had come to an end; but as soon as Abu Bakr added, "Behold, whoever has worshipped Muhammad may know that Muhammad has died; but whoever worships God may know that God is ever-living, and never dies" (Bukhari), all confusion was stilled. - The expression "turning about on one's heels" denotes - according to circumstances - either actual apostasy or a deliberate withdrawal from efforts in the cause of God.
Malik Quran Translation
Muhammad is no more than a Rasool of Allah, like the Rasools that passed away before him. If he dies or is killed will you turn back on your heels (become unbelievers)? He that turns back on his heels will do no harm to Allah; but Allah will reward the thankful.
Yusuf Ali Quran Translation
Muhammad is no more than an Apostle: many were the Apostles that passed away before him. If he died or were slain will ye then turn back on your heels? If any did turn back on his heels not the least harm will he do to Allah; but Allah (on the other hand) will swiftly reward those who (serve him) with gratitude. 460
This verse primarily applies to the battle of Uhud, in the course of which a cry was raised that the Messenger was slain. He had indeed been severely wounded, but Talha, Abu Bakr, and Ali were at his side, and his own unexampled bravery saved the Muslim army from a rout. This verse was recalled again by Abu Bakr when the Messenger actually died a natural death eight years later, to remind people that Allah, Whose Message he brought, lives for ever. And have need to remember this now and often for two reasons: (1) when we feel inclined to pay more than human honour to one who was the truest, the purest, and the greatest of men, and thus in a sense to compound for our forgetting the spirit of his teaching, and (2) when we feel depressed at the chances and changes of time, and forget that Allah lives and watches over us and over all His creatures now as in a history in the past and in the future.
Mustafa Khattab Quran Translation
Muḥammad is no more than a messenger; other messengers have gone before him. If he were to die or to be killed, would you regress into disbelief? Those who do so will not harm Allah whatsoever. And Allah will reward those who are grateful.
Piktal Quran Translation
Muhammad is but a messenger, messengers (the like of whom) have passed away before him. Will it be that, when he dieth or is slain, ye will turn back on your heels? He who turneth back doth no hurt to Allah, and Allah will reward the thankful.
Wama muhammadun illa rasoolun qad khalat min qablihi alrrusulu afain mata aw qutila inqalabtum AAala aAAqabikum waman yanqalib AAala AAaqibayhi falan yadurra Allaha shayan wasayajzee Allahu alshshakireena