Pope St. John Paul II
“The Eucharist is the Sacrament in which our new being is most completely expressed and in which Christ himself unceasingly and in an ever new manner ‘bears witness’ in the Holy Spirit to our spirit that each of us, as a sharer in the mystery of the Redemption, has access to the fruits of the filial reconciliation with God that he himself actuated and continually actuates among us by means of the Church’s ministry.”
Source: Pope St. John Paul II, REDEMPTOR HOMINIS, 3/4/79