Praise be to Allaah.
It was narrated that Zayd ibn Khaalid al-Juhani said: The Messenger of Allaah (peace and blessings of Allaah be upon him) said: Whoever gives iftaar to one who is fasting will have a reward like his, without that detracting from the reward of the fasting person in the slightest.
Narrated by al-Tirmidhi, 807; Ibn Maajah, 1746. Classed as saheeh by Ibn Hibaan, 8/216 and by al-Albaani in Saheeh al-Jaami, 6415.
Shaykh al-Islam [Ibn Taymiyah] said: What is meant by giving him iftaar is giving him enough to satisfy him. Al-Ikhtiyaaraat, p. 194
The righteous salaf were keen to provide food for others and they thought that this was one of the best of righteous deeds.
One of the salaf said: For me to invite ten of my companions and feed them food that they like is dearer to me than freeing ten of the sons of Ismaa'eel from slavery.
Many of the salaf used to give up their iftaar for others, such as Abd-Allaah ibn Umar (may Allaah be pleased with him), Dawood al-Taa'i, Maalik ibn Dinar and Ahmad ibn Hanbal. Ibn Umar used only to break his fast with orphans and the poor and needy.
There were among the salaf those who used to offer food to their brothers whilst fasting, and they would sit and serve them, such as al-Hasan and Ibn al-Mubaarak.
Abu al-Siwaar al-Adawi said: Men from the tribe of Banu Adiyy used to pray in this mosque and not one of them would break his fast on his own; if they found someone to join them they would eat with him, otherwise they would take their food out to the mosque and eat with the people, and the people would eat with them.
From the ibaadah of providing food for people stem many other acts of worship such as creating love and friendship towards those who are given the food, which is a means of entering Paradise, as the Prophet (peace and blessings of Allaah be upon him) said: You will not enter Paradise until you truly believe, and you will not truly believe until you love one another. Narrated by Muslim, 54. It also fosters the practice of sitting with righteous people and seeking reward by helping them to do acts of worship for which they gain strength by eating your food.