Langar (Sufism)

Langar (Persian: لنگر) is an institution developed and maintained by Sufi Muslims of South Asia, particularly Pakistan and India, whereby food and drink are provided to the needy regardless of ethnic, caste or religious background. Its origin is from Sufism (Islam) because serving of food to the needy has been a rich tradition among Sufis, especially of the Chishti Order. There is extensive use of free food imagery and metaphor in Sufi writings. Sugar and other sweet foods represent the sweetness of piety and community with God, while salt symbolizes purity and incorruptibility. Through the pronouncement of Bismallah during the bread-making process, the bread is imbued with spiritual power or barakat, which is shared by those who eat the bread. The transformation of the raw wheat to finished bread is used as an analogy for Sufi spiritual development.
Sufi ritual observances (dhikr) are concerned with remembrance of God through exaltation and praise. Singing, dancing, and drumming are commonly part of such rituals, as is sharing of food. 
The tradition of Langar was also adopted by the Sikh community, where it goes by the same name.
Food is served out of a massive pot called a "deg" in the precincts of a dargah (Sufi shrine). It is also actively distributed to the poor.
Etymology.
"Langar" is originally a Persian word, and later came into Urdu and Punjabi from it, and in Bengali as "longor" ().
History.
Langar, the practice and institution, was first started by Baba Farid, a Muslim of the Chishti Sufi order. The institution of the langar was already popular in the 12th and 13th century among Sufis (Muslim mystics) of the Indian subcontinent. The practice grew and is documented in the "Jawahir al-Faridi" compiled in 1623 CE. It was later, both the institution and term, adopted by Sikhs.