[Taken from the Hermeneutic of Continuity]
The great theologian, Maurice de la Taille, wrote a monumental work of scholarship Mysterium Fidei of which I was fortunate indeed to acquire a copy recently from the library of a deceased priest.
He spoke particularly of the relationship between the Last Supper, the crucifixion, and the offering of the Mass. If I remember correctly, he spoke of:
1. oblatio victimae immolandae
(the offering of the victim to be immolated - the Last Supper)
2. immolatio victimae oblatae
(the immolation of the victim that had been offered - the crucifixion)
3. oblatio victimae immolatae
(the offering of the victim that had been immolated - the Mass)
The Triduum could be understood in these terms. At the evening Mass of Maundy Thursday, we commemorate particularly the offering of the sacrifice made by Christ when he said "This is my body which will be given for you" ... "This is the chalice of my blood which will be poured out for you."
On Good Friday, we commemorate the immolation of the victim who had offered by offering himself. "It is consummated" - the sacrifice is complete and there will never again need to be another new sacrifice. Christ has offered himself finally, definitively, effectively, for the redemption of the human race.
At the Easter Vigil, we once again offer the Holy Sacrifice of the Mass: one and the same as the sacrifice of Calvary. The victim who has been slain for our salvation is offered on our altar by the Church through the ministry of the priest and he "lives for ever to intercede for us," truly God and truly man, the one and perfect Mediator.
Throughout the year, these mysteries are celebrated and made present in the Liturgy. During the Triduum, we ponder them at greater depth over three days, savouring their meaning more fully, and genuinely taking part by offering our own lives in union with the Divine Victim.