Evidence from the Quran
The first verse
32- Allah, Exalted is He, says: “And among mankind is he who sells himself, seeking the pleasure of Allah; and Allah is Ever-Kind to His servants” (al-Baqarah 2:207).
Reason for revelation
33- It is related that the occasion for which this verse was sent down1 was as follows: Suhayb set out from Mecca to emigrate to the Prophet ﷺ in Medina, travelling alone. The idolaters pursued him. He quickly took an arrow from his quiver and said, “By Allah, not one of you will come near me without my shooting him.” He intended to fight them single-handedly, then said, “If you would like to take my property in Mecca, take it—I will even show you where it is.” He subsequently reached the Prophet ﷺ, who greeted him with the words, “A profitable sale indeed, Abū Yahyā!”
(1) Ibn al-Nahhas states, after citing several Qurʾanic commentators who give the occasion of revelation for this verse in the wording preserved by Shaykh al-Islam—among them Ibn Abi Hatim and Abu Bakr al-Mundhiri—: “A group of other exegetes have also reported the story of Suhayb, in addition to those we have just mentioned, such as Ibn Marduyah, al-Wahidi, al-Qurtubi and others. Ibn Kathir of Damascus further remarks: ‘Most scholars understand that the verse was revealed about every combatant in the path of Allah, as the Almighty says: Indeed, Allah has purchased from the believers their lives and their wealth in exchange for Paradise.’” Mashariʿ al-Anwar, 1/523.
See also: Ibn Hajar, al-ʿIjab fi Bayan al-Asbab, 1/525–526; al-Qurtubi, Tafsir, 3/20; al-Tabari, Tafsir, 2/321; al-Baghawi, Tafsir, 2/329; Ibn al-Jawzi, Zad al-Masir, 1/223; al-Suyuti, al-Durr al-Manthur, 1/577; al-Alusi, Ruh al-Maʿani, 2/97.