so they killed him and took the provisions he had with him. Then Allah revealed: {O you who have believed, when you travel in the way of Allah, investigate; and do not say to one who gives you [a greeting of] peace, "You are not a believer"}, because the greeting of the believers is peace; by it they know one another and meet one another. {Do you desire the temporary goods of worldly life, for with Allah are many spoils [of war]} that He will give to you. {Thus you were before}, meaning: in error, {so Allah conferred His favor upon you} with Islam.

Muhammad said: And whoever reads {to one who gives you [a greeting of] al-salam (submission)}, the meaning is: submits to you. [Verses 95-96]