Catechism of the Catholic Church
947 - "Since all the faithful form one body, the good of each is communicated to the others. . . . We must therefore believe that there exists a communion of goods in the Church. But the most important member is Christ, since he is the head. . . . Therefore, the riches of Christ are communicated to all the members, through the sacraments." "As this Church is governed by one and the same Spirit, all the goods she has received necessarily become a common fund."
1475 - In the communion of saints, "a perennial link of charity exists between the faithful who have already reached their heavenly home, those who are expiating their sins in purgatory and those who are still pilgrims on earth. between them there is, too, an abundant exchange of all good things." In this wonderful exchange, the holiness of one profits others, well beyond the harm that the sin of one could cause others. Thus recourse to the communion of saints lets the contrite sinner be more promptly and efficaciously purified of the punishments for sin.