Pope St. John Paul II
“It is an essential truth, not only of doctrine but also of life, that the Eucharist builds the Church, building it as the authentic community of the People of God, as the assembly of the faithful, bearing the same mark of unity that was shared by the Apostles and the first disciples of the Lord. The Eucharist builds ever anew this community and unity, ever building and regenerating it on the basis of the Sacrifice of Christ, since it commemorates his death on the Cross, the price by which he redeemed us.”
Source: Pope St. John Paul II, REDEMPTOR HOMINIS, 3/4/79