St. John Chrysostom vigorously recalls this: "Not to enable the poor to share in our goods is to steal from them and deprive them of life. The goods we possess are not ours, but theirs." "The demands of justice must be satisfied first of all; that which is already due in justice is not to be offered as a gift of charity":
When we attend to the needs of those in want, we give them what is theirs, not ours. More than performing works of mercy, we are paying a debt of justice.
Source: Catechism of the Catholic Church (Vatican.va)