47 At the Last Supper, on the night when He was betrayed, our Saviour instituted the eucharistic sacrifice of His Body and Blood. He did this in order to perpetuate the sacrifice of the Cross throughout the centuries 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 eaten, the mind is filled with grace, and a pledge of future glory is given to us .
Source: Sacrosanctum Concilium (Vatican.va)