To pray in order to gain the indulgence means to enter into this spiritual communion and therefore to open oneself totally to others. In the spiritual realm, too, no one lives for himself alone. And salutary concern for the salvation of one's own soul is freed from fear and selfishness only when it becomes concern for the salvation of others as well. This is the reality of the communion of saints, the mystery of “vicarious life”, of prayer as the means of union with Christ and his saints. He takes us with him in order that we may weave with him the white robe of the new humanity, the robe of bright linen which clothes the Bride of Christ.
This doctrine on indulgences therefore “teaches firstly how sad and bitter it is to have abandoned the Lord God
(cf. Jer 2:19). When they gain indulgences, the faithful understand that by their own strength they would not be able to make good the evil which by sinning they have done to themselves and to the entire community, and therefore they are stirred to saving deeds of humility”.(18) Furthermore, the truth about the communion of saints which unites believers to Christ and to one another, reveals how much each of us can help others — living or dead — to become ever more intimately united with the Father in heaven.