1807 Justice is the moral virtue that consists in the constant and firm will to give their due to God and neighbor. Justice toward God is called the “virtue of religion.” Justice toward men disposes one to respect the rights of each and to establish in human relationships the harmony that promotes equity with regard to persons and to the common good. The just man, often mentioned in the Sacred Scriptures, is distinguished by habitual right thinking and the uprightness of his conduct toward his neighbor. “You shall not be partial to the poor or defer to the great, but in righteousness shall you judge your neighbor.” “Masters, treat your slaves justly and fairly, knowing that you also have a Master in heaven.”
2447 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:
As you can see, it would be almost impossible to fight for justice, without mercy. The two go hand-in-hand.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?