The "Constitution on the Sacred Liturgy" of the Second Vatican Council: "At the Last Supper, on the night He was betrayed, our Savior instituted the Eucharistic sacrifice of His Body and Blood. This He did in order to perpetuate the sacrifice on the cross through the ages until He should come again, and so to entrust to His beloved spouse, the Church, a memorial of His death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a paschal banquet in which Christ is consumed, the mind is filled with grace, and a pledge of future glory is given to us" (No. 47).
The actual sacrifice of Christ on the cross and the sacrifice of the Mass are inseparably united as one single sacrifice.
The Meaning of the Mass - Venerable Fulton Sheen