A poor, an orphan and a captive

Some scholars of Tafseer tell us, about the cause of revelation of the following verses:

And they give food, in spite of their love for it [or for the love of Him], to the Miskeen [the poor], the orphan, and the captive [saying], 'We feed you seeking Allah's Countenance only. We wish for no reward, nor thanks from you. (Quran 76:8-9)

They said: " 'Ali and Faitimah were observing fast one day and that they had prepared, for breaking their fast, a kind of food that contained some butter. When the sun set and they sat down for breaking the fast, they heard a knock on their door. 'Ali stood up and asked, 'Who is that?' A voice answered, 'A hungry poor man.'Ali went back inside brought the food together into a bag and gave to that poor man who thanked him and supplicated for him. So he and Fatimah broke their fast on only bread and water. On the following day, and at the same time, when 'Ali and his
wife Fatimah were about to take the morsel of their food, there was a knock on the door. 'Ali stood up and asked, 'Who is that?' A voice came from outside, 'An orphan who is displaced and starving.' 'Ali did as he did the day before. He carried the food in a bag to that orphan. And he and his wife broke their fast on bread and water, without feeling any inconvenience or displeasure. The incidence repeated itself on the third day and the knocking man answered that he was a captive. So 'Ali gave him the food he and his wife wanted to break their fast with. And as they did in the two previous days, they broke their fast on only bread and water.

Do you think that the person who knocked the door on those three days was the same person, or different persons: a poor man, an orphan and a captive? Narrations of the scholars of Tafseer indicate that the knocker was Angel Gabriel who came to test the faith and patience of' Ali and Fatimah. For, after that, Jibreel came to the Messenger of Allah (Peace be upon him) and informed him of the incident. He gave him good tiding that 'Ali and Fatimah would have a carriage of silver in Paradise as a suitable reward."

Source: Women around the messenger / page:328/329