119 When these means which We have pointed out do not fulfill the needs, particularly of a larger or poorer family, Christian charity towards our neighbor absolutely demands that those things which are lacking to the needy should be provided; hence it is incumbent on the rich to help the poor, so that, having an abundance of this world's goods, they may not expend them fruitlessly or completely squander them, but employ them for the support and well-being of those who lack the necessities of life. They who give of their substance to Christ in the person of His poor will receive from the Lord a most bountiful reward when He shall come to judge the world; they who act to the contrary will pay the penalty. Not in vain does the Apostle warn us: "He that hath the substance of this world and shall see his brother in need, and shall shut up his bowels from him: how doth the charity of God abide in him?"
Source: Casti Connubii (Vatican.va)