22 Therefore, those whom fortune favors are warned that riches do not bring freedom from sorrow and are of no avail for eternal happiness, but rather are obstacles;(9) that the rich should tremble at the threatenings of Jesus Christ - threatenings so unwonted in the mouth of our Lord(10) - and that a most strict account must be given to the Supreme Judge for all we possess. The chief and most excellent rule for the right use of money is one the heathen philosophers hinted at, but which the Church has traced out clearly, and has not only made known to men's minds, but has impressed upon their lives. It rests on the principle that it is one thing to have a right to the possession of money and another to have a right to use money as one wills. Private ownership, as we have seen, is the natural right of man, and to exercise that right, especially as members of society, is not only lawful, but absolutely necessary. "It is lawful," says St. Thomas Aquinas, "for a man to hold private property; and it is also necessary for the carrying on of human existence."" But if the question be asked: How must one's possessions be used? - the Church replies without hesitation in the words of the same holy Doctor: "Man should not consider his material possessions as his own, but as common to all, so as to share them without hesitation when others are in need. Whence the Apostle with, ‘Command the rich of this world... to offer with no stint, to apportion largely.’"(12) True, no one is commanded to distribute to others that which is required for his own needs and those of his household; nor even to give away what is reasonably required to keep up becomingly his condition in life, "for no one ought to live other than becomingly."(13) But, when what necessity demands has been supplied, and one's standing fairly taken thought for, it becomes a duty to give to the indigent out of what remains over. "Of that which remaineth, give alms."(14) It is a duty, not of justice (save in extreme cases), but of Christian charity - a duty not enforced by human law. But the laws and judgments of men must yield place to the laws and judgments of Christ the true God, who in many ways urges on His followers the practice of almsgiving - ‘It is more blessed to give than to receive";(15) and who will count a kindness done or refused to the poor as done or refused to Himself - "As long as you did it to one of My least brethren you did it to Me."(16) To sum up, then, what has been said: Whoever has received from the divine bounty a large share of temporal blessings, whether they be external and material, or gifts of the mind, has received them for the purpose of using them for the perfecting of his own nature, and, at the same time, that he may employ them, as the steward of God's providence, for the benefit of others. "He that hath a talent," said St. Gregory the Great, "let him see that he hide it not; he that hath abundance, let him quicken himself to mercy and generosity; he that hath art and skill, let him do his best to share the use and the utility hereof with his neighbor."(17)
Source: Rerum Novarum (Vatican.va)