Al-Layl 92:21

According to the reports, Abu Bakr used to buy and free weak, unprotected Muslim slaves who were being tortured in Mecca, foremost among them Bilal the Abyssinian, spending much of his wealth in the process. When it was suggested that he free strong men who could then protect him, he replied that he did it only for God's sake. The verses "But the most God-fearing will be kept away from it (the Fire): he who gives his wealth to purify himself, owing no favor to anyone that must be repaid, seeking only the face of his Lord Most High" are reported to have been revealed concerning him.

Vâhidî, Esbâbü'n-Nüzûl; İbn Ebî Hâtim

Surah al-Layl is Meccan, held to belong to the early Meccan period. Declaring that people's strivings are diverse, it contrasts the one who gives and is mindful of God with the one who is miserly and deems himself self-sufficient. Some reports state that the closing verses, praising the one who gives his wealth to purify himself for God's sake, were revealed concerning Abu Bakr, who purchased and freed persecuted slaves.

Klasik tefsir mukaddimeleri; Vâhidî, Esbâbü'n-Nüzûl