“It was necessary accordingly that there should be at all times among men something to show forth our Lord’s Passion; the chief sacrament of which in the old Law was the Paschal Lamb. Hence the Apostle says (1 Cor. 5:7): ‘Christ our Pasch is sacrificed.’ But its successor under the New Testament is the sacrament of the Eucharist, which is a remembrance of the Passion now past, just as the other was figurative of the Passion to come.” -St. Thomas Aquinas