The works of mercy are 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:
He who has two coats, let him share with him who has none and he who has food must do likewise. But give for alms those things which are within; and behold, everything is clean for you. If a brother or sister is ill-clad and in lack of daily food, and one of you says to them, "Go in peace, be warmed and filled," without giving them the things needed for the body, what does it profit?
Source: Catechism of the Catholic Church (Vatican.va)