Catechism re Communion
1212 The faithful … receive in the Eucharist the food of eternal life.
1391 The principal fruit of receiving … Holy Communion is an intimate union with Christ Jesus.
1324 For in the blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself
1350 …Christ, who in his sacrifice, brings to perfection all human attempts to offer sacrifices.
1392 What material food produces in our bodily life, Holy Communion wonderfully achieves in our spiritual life. Communion with the flesh of the risen Christ, a flesh “given life and giving life through the Holy Spirit,” preserves, increases, and renews the life of grace received at Baptism. This growth in Christian life needs the nourishment of Eucharistic Communion,
1394 As bodily nourishment restores lost strength, so the Eucharist strengthens our charity … and this living charity wipes away venial sins. by giving himself to us Christ revives our love…
1211 The Eucharist occupies a unique place as the “Sacrament of sacraments”: “all the other sacraments are ordered to it as to their end.”
1074 “The liturgy is the summit toward which the activity of the Church is directed; it is also the font from which all her power flows.”
1331 Holy Communion,…by this sacrament we unite ourselves to Christ, who makes us sharers in his Body and Blood to form a single body.
1333 The signs of bread and wine become, in a way surpassing understanding, the Body and Blood of Christ; they continue also to signify the goodness of creation.
1104 Christian liturgy not only recalls the events that saved us but actualizes them, makes them present. The Paschal mystery of Christ is celebrated, not repeated.
1366 The Eucharist is thus a sacrifice because it re-presents (makes present) the sacrifice of the cross,… [he wanted] to leave to his beloved spouse the Church a visible sacrifice (as the nature of man demands) by which the bloody sacrifice which he was to accomplish once for all on the cross would be re-presented,
1085 His Paschal mystery is a real event that occurred in our history, but it is unique: all other historical events happen once, and then they pass away, swallowed up in the past. The Paschal mystery of Christ, by contrast, cannot remain only in the past, because by his death he destroyed death, and all that Christ is – all that he did and suffered for all men – participates in the divine eternity, and so transcends all times while being made present in them all. The event of the Cross and Resurrection abides and draws everything toward life.
1393 The Eucharist cannot unite us to Christ without at the same time cleansing us from past sins and preserving us from future sins: