"Dear brothers and sisters, the Eucharist is at the root of every form of holiness, and each of us is called to the fullness of life in the Holy Spirit." Source: St. Alphonsus Liguori, Visits to the Most Holy Sacrament
"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 [...]
"The Holy Spirit does not speak to a soul that is distracted and garrulous. He speaks by His quiet inspirations to a soul that is recollected, to a soul that knows how to keep silence. If silence were strictly observed, there would not be any grumbling, bitterness, slandering, or gossip, and charity would not be [...]
"At the center of the Church is the Eucharist, where Christ is present and active in humanity and in the whole world by means of the Holy Spirit." Source: Pope St. John Paul II, General Audience, September 13, 1989
"In the Eucharist Christ gives us his body and blood as food and drink, under the appearance of bread and wine, just as during the paschal meal at the Last Supper. Only through the Spirit, the giver of life, can the Eucharistic food and drink produce in us 'communion,' that is to say, the salvific [...]
"Ah! it is the Holy Spirit who desires to pray in us! Of ourselves, we are incapable of doing so; but the Spirit of Jesus Christ, who abides in us, wishes to help our impotence and to pray by His ineffable groanings. Then, let this Spirit of love speak and pray. The prayer that comes [...]
"Since the Eucharist mystically renews Christ's redemptive sacrifice, one can easily see the intrinsic link between this sacrament and the gift of the Spirit. In founding the Church through his coming on the day of Pentecost, the Holy Spirit established it in objective relationship to the Eucharist, and ordered it toward the Eucharist." Source: [...]