In the Christian tradition, “the acts of mercy” are general practices that all adherents are expected to perform as part of their devotion. These ethical habits, which fulfill the material and non-material needs of human beings, are simply defined in paragraph 2447 of the Catechism of the Catholic Church as:
charitable actions by which we come to the aid of our neighbor in his spiritual and bodily necessities. Instructing, advising, consoling, comforting are spiritual works of mercy, as are forgiving and bearing wrongs patiently. The corporal works of mercy consist especially in feeding the hungry, sheltering the homeless, clothing the naked, visiting the sick and imprisoned, and burying the dead. Among all these, giving alms to the poor is one of the chief witnesses to fraternal charity: it is also a work of justice pleasing to God…
Out of the ‘spiritual’ and ‘bodily’ works (enumerations of seven each) prescribed, it is the latter set, understandably, that has been explored more easily through visual art. The source for the first six of the bodily or corporal works of mercy – (1) feeding the hungry, (2) giving drink to the thirsty, (3) sheltering the homeless (4) clothing the naked (5) visiting the sick and (6) visiting the imprisoned – is Christ’s parable of the Sheep and the Goats in Matthew 25:31-46. They are the criteria for ultimate divine judgement. It is on the basis of these acts that an adherent is declared righteous or unrighteous and directed to heaven or hell, respectively. The last corporal work, (7) burying the dead, is adopted from the Old Testament book of Tobit (1:17-19) – included in the Catholic and Orthodox but not the Protestant biblical canon. It was added to the list in 1207 by Pope Innocent III.
Here are a few depictions:
(Most can be clicked on and enlarged further. Additional links of interest are provided below the pictures.)