Not a souvenir
The Mass is not a souvenir. When you go to Mass it is not the same as going, for example, to Calvary and chipping away a rock and saying, “This is a souvenir of the place where our Lord died.” No, the Mass is a vision; it is an action in time and in eternity. It is in time, because we see it taking place before our eyes on the altar. It is also in eternity, as regards the value of redemption. All the merits of our Lord's death, Resurrection, ascension, and glorification are applied to us. We unite ourselves with that great eternal act of love. The Mass, then, is not a distinct sacrifice from the cross. If we at the Mass close our eyes and concentrate on that mystery, we are in effect with Mary, and Magdalen, and John at the foot of the cross.