(And strain not thine eyes…) [20:131].
Ahmad ibn Muhammad ibn Ibrahim al-Tha‘labi informed us> Shu‘ayb ibn Muhammad al-Bayhaqi> Makki ibn ‘Abdan> Abu’l-Azhar> Rawh> Musa ibn ‘Ubaydah al-Rabdhi> Yazid ibn ‘Abd Allah ibn Qusayt> Abu Rafi‘, the client of the Messenger of Allah, Allah bless him and give him peace, who reported that a guest dropped by the Messenger of Allah, Allah bless him and give him peace, and so he summoned me and asked me to go to a Jewish man who sold food. He entrusted me to tell him: “Muhammad, the Messenger of Allah, Allah bless him and give him peace, has received a guest and does not have what to offer him for food. Could you sell me such-and-such measure of ground wheat or lend me some food which I will repay at the appearance of the moon of Rajab”. The Jew said: “I will not sell him or lend him except in exchange for a security”. I went back to the Prophet, Allah bless him and give him peace, and when I repeated what the Jew had said, he exclaimed: “By Allah, I am trustworthy in heaven as I am trustworthy on earth. Had he sold to me or lent me, I would have paid back. Take my armour as security”. This verse was revealed to consol him about this world (And strain not thine eyes toward that which We cause some wedded pairs among them to enjoy, the flower of the life of the world, that We may try them thereby…).
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou