Al 'Imran, 144 Ayah
3:144
وَمَا مُحَمَّدٌ إِلَّا رَسُولٞ قَدۡ خَلَتۡ مِن قَبۡلِهِ ٱلرُّسُلُۚ أَفَإِيْن مَّاتَ أَوۡ قُتِلَ ٱنقَلَبۡتُمۡ عَلَىٰٓ أَعۡقَٰبِكُمۡۚ وَمَن يَنقَلِبۡ عَلَىٰ عَقِبَيۡهِ فَلَن يَضُرَّ ٱللَّهَ شَيۡـٔٗاۚ وَسَيَجۡزِي ٱللَّهُ ٱلشَّٰكِرِينَ ١٤٤
Wa Mā Muĥammadun 'Illā Rasūlun Qad Khalat Min Qablihi Ar-Rusulu ۚ 'Afa'īn Māta 'Aw Qutila Anqalabtum `Alá 'A`qābikum ۚ Wa Man Yanqalib `Alá `Aqibayhi Falan Yađurra Al-Laha Shay'āan ۗ Wa Sayajzī Al-Lahu Ash-Shākirīna
Muhammad is not but a messenger. [Other] messengers have passed on before him. So if he was to die or be killed, would you turn back on your heels [to unbelief]? And he who turns back on his heels will never harm Allah at all; but Allah will reward the grateful.