CCC 1334
© Libreria Editrice Vaticana Source: vatican.va
In the Old Covenant bread and wine were offered in sacrifice among the first fruits of the earth as a sign of grateful acknowledgment to the Creator. But they also received a new significance in the context of the Exodus: the unleavened bread that Israel eats every year at Passover commemorates the haste of the departure that liberated them from Egypt; the remembrance of the manna in the desert will always recall to Israel that it lives by the bread of the Word of God; Cf. Deut 8:3. their daily bread is the fruit of the promised land, the pledge of God's faithfulness to his promises. The "cup of blessing" 1 Cor 10:16. at the end of the Jewish Passover meal adds to the festive joy of wine an eschatological dimension: the messianic expectation of the rebuilding of Jerusalem. When Jesus instituted the Eucharist, he gave a new and definitive meaning to the blessing of the bread and the cup.
Read the full chapter 1. The Sacraments of Christian Initiation ¶1212–1419