Quran 3:144 Ali 'Imran, ayah 144 of 200

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 ۝١٤٤

3:144 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 on his heels doth no hurt to Allah, and Allah will reward the thankful.