Muḥammad 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 Allāh at all; but Allāh will reward the grateful.
Muhammad is only a Messenger like the messengers of Allah who came before him, who died or were killed. If he were to die or be killed would you turn back from your faith, and stop fighting? Whoever among you turns back from his faith will not harm Allah in any way. He is the Strong, the Victorious. Such a person only harms himself by exposing himself to loss in this world and the Afterlife. Allah will reward those who are thankful to Him by making them firm in their faith and in struggling for His sake.