The following holy Verse was revealed for Ali and his family: "They feed the destitute, orphans, and captives for the love of Allah, saying: We only feed you for the sake of Allah and we do not want any reward or thanks from you (76:9)."
The disciples of The The Ahl ul-Bayt have unanimously agreed that the previous holy Verse was revealed for Ali, Fatima, al-Hasan, and al-Hussein (a). Moreover, a good deal of ulema of other sects have also asserted so.
Interpreting Sura of al-Insan, az-Zamakhshari records the following narration in his book titled Tafsir ul-Keshaf:
Ibn Abbas narrated:
The Prophet (s), with some of his companions, visited al-Hasan and al-Hussein who were sick. They suggested that Imam Ali should vow a three-day fasting if they would recover their health. The Imam, as well as their mother Fatima and Fudda their bondwoman implemented that suggestion. When al-Hasan and al-Hussein were healed, the group fasted. The Imam had no food at that time; therefore, he had to borrow three measures of barley from Shimon the Jew. In the first day, Fatima (a) milled and baked one of these measures. In the very time of breaking fast, a poor man knocked their door and said: "Peace be upon you; the family of Mohammed. I am a poor Muslim. Serve me with food and God may serve you from the food of Paradise." The Imam gave him his share. The others pursued him and gave their shares. They passed that night without eating anything. On the second day of their fasting, an orphan complaining hunger knocked their door in the time of breaking fast. They offered their shares and passed the second night without having anything except water. On the third day and in the very time of breaking fast, a prisoner complaining hunger knocked their door asking for some food. They all offered him their shares before having anything of it.