Pope Pius XII – Mediator Dei: 29,73,79
73. The third end proposed is that of expiation, propitiation and reconciliation. Certainly, no one was better fitted to make satisfaction to Almighty God for all the sins of men than was Christ. Therefore, He desired to be immolated upon the cross “as a propitiation for our sins, not for ours only but also for those of the whole world” and likewise He daily offers Himself upon our altars for our redemption, that we may be rescued from eternal damnation and admitted into the company of the elect. This He does, not for us only who are in this mortal life, but also “for all who rest in Christ, who have gone before us with the sign of faith and repose in the sleep of peace;” for whether we live, or whether we die “still we are not separated from the one and only Christ.”
79. The august sacrifice of the altar is, as it were, the supreme instrument whereby the merits won by the divine Redeemer upon the cross are distributed to the faithful: “as often as this commemorative sacrifice is offered, there is wrought the work of our Redemption.”118. For since by feasting upon the bread of angels we can by a “sacramental” communion, as we have already said, also become partakers of the sacrifice, she repeats the invitation to all her children individually, “Take and eat. . . Do this in memory of Me” so that “we may continually experience within us the fruit of our redemption” in a more efficacious manner.