1. The Eucharist is a complex, many-sided reality (see S.t., 3, q. 73, aa. 2–4; q. 79, aa. 1, 2, 4, 6). The Council of Trent lists five reasons for Jesus’ institution of this most holy sacrament (see DS 1638/875).1 First, it is a remembrance of the works of Jesus, to be received to preserve his memory and proclaim his death until he comes (see 1 Cor 11.23–26). Second, it is spiritual food, to sustain and build up those who live with Jesus’ life (see Mt 26.26; Jn 6.53–58). Third, it is to free us from daily defects and keep us from mortal sin. Fourth, it is a pledge or down payment on our future glory and everlasting happiness; by it we begin to be in heaven even during this life. Fifth, it is a symbol of the Mystical Body whose head is Jesus (see Eph 5.23); as Jesus wills, its worthy reception strengthens the bonds of faith, hope, and charity which unite members of the Church.
Essentially the same points are made by Vatican II at the beginning of its chapter on the mystery of the Eucharist: “At the Last Supper, on the night when he was betrayed, our Savior instituted the Eucharistic Sacrifice of his Body and Blood. He did this in order to perpetuate the sacrifice of the Cross throughout the centuries until he should come again, and so to entrust to his beloved spouse, the Church, a memorial of his death and resurrection: a sacrament of love, a sign of unity, a bond of charity, a paschal banquet in which Christ is consumed, the mind is filled with grace, and a pledge of future glory is given to us” (SC 47). The only difference between Trent and Vatican II is that the latter does not explicitly mention the role of the Eucharist in overcoming venial sin and keeping us from mortal sin, but says instead simply that in the Eucharist “the mind is filled with grace.”
2. Besides the rich complexity of its purposes, the Eucharist also involves another complexity, arising from the fact that it is a divine-human communion of love. United in the human life of Jesus are the revelatory signs and the human response of the Word Incarnate (21‑F). The Eucharist, as well as the other sacraments by relationship to it, make Jesus’ human redemptive act present to us, inasmuch as this act exists in him as he now is in glory and is outwardly enacted in the sacramental rites (see S.t., 3, q. 62, a. 5; q. 65, a. 3; q. 79, a. 1). Hence, the Eucharist as well as the other sacraments must be understood both as a revelatory sign, communicating divine truth and love to us, and as a human response of sacrifice in thanksgiving for the great good—namely, himself—which God shares with us in Jesus.
The structure of our Mass is like the structure of the making of the covenant of Sinai: The law is read to the people; they respond with an expression of acceptance and commitment; the agreement is sealed in blood; and a covenant meal is shared in the presence of God (see Ex 24.3–11). Similarly, we hear the word of God in the gospel and respond in faith; the baptismal commitment is consummated by sealing with the blood of Jesus; and he, both priest and victim, becomes our food in holy Communion. The difference between the ancient ceremony and the new rite of Jesus is that the Mass consummates an infinitely more intimate relationship: “For the law was given through Moses; grace and truth came through Jesus Christ” (Jn 1.17). The old covenant was an engagement between God and humankind; the new is marriage, fruitful in divine children.
3. In the liturgy of the Mass, we first receive the word of the Lord calling us to intimacy and guiding and shaping our lives; next we receive our Lord Jesus in Communion: him bodily, the power of his Spirit, and his life as principle of our lives; finally, we receive the commission to go forth to love and serve the Lord. We receive all these gifts inasmuch as the Mass is truly revelatory, truly communicative of divine truth and love.
4. In the liturgy of the Mass we also act. We give a gift, as human persons united with Jesus our head and priest. Since we are baptized, the human goods realized in us and the fruits of our work are already holy in God’s sight, just as Jesus was already holy when he undertook his sacrificial life. At the offertory, we offer what we are and have, to be formed into Jesus at the consecration. With him, we then offer to the Father both Jesus and ourselves, now united as one. We make these offerings inasmuch as the Mass is truly a fitting response to God—acceptance of all he gives and a loving return of it all to him.
5. It should therefore be clear how complex the Eucharist is. But it is also simple. Its complexity is not that of a multiplicity of unrelated purposes and disjointed parts, but of a very perfect, endlessly rich relationship: the communion of charity. God loves us, gives himself to us, gives us a perfect response, and we make this response our own through, with, and in our Lord Jesus. Thus we are fully ourselves but perfectly united with Jesus.
Near the beginning of his apostolic letter, Dominicae cenae, John Paul II reaffirms that
. . . Eucharistic worship constitutes the soul of all Christian life. In fact Christian life is expressed in the fulfilling of the greatest commandment, that is to say in the love of God and neighbour, and this love finds its source in the Blessed Sacrament, which is commonly called the Sacrament of love.
Here the complexity of the Eucharist is reduced to its central simplicity, the simplicity of communion in divine love, of which the Eucharist is the sacrament (see S.t., 3, q. 73, a. 3, ad 3; q. 75, a. 1; q. 79, aa. 1, 4). That love is revealed in Jesus’ sacrifice, we respond to it, and by participation in this sacrament we grow toward the maturity of heavenly completion in our Lord Jesus by becoming ever more closely united, even during our earthly life, with him.
The Eucharist signifies this charity, and therefore recalls it, makes it present and at the same time brings it about. Every time that we consciously share in it, there opens in our souls a real dimension of that unfathomable love that includes everything that God has done and continues to do for us human beings, as Christ says: “My Father goes on working, and so do I” (Jn 5.17). Together with this unfathomable and free gift, which is charity revealed in its fullest degree in the saving Sacrifice of the Son of God, the Sacrifice of which the Eucharist is the indelible sign, there also springs up within us a lively response of love. We not only know love; we ourselves begin to love. We enter, so to speak, upon the path of love and along this path make progress. Thanks to the Eucharist, the love that springs up within us from the Eucharist develops in us, becomes deeper and grows stronger.
Eucharistic worship is therefore precisely the expression of that love which is the authentic and deepest characteristic of the Christian vocation. This worship springs from the love and serves the love to which we are all called in Jesus Christ [note omitted]. A living fruit of this worship is the perfecting of the image of God that we bear within us, an image that corresponds to the one that Christ has revealed to us. As we thus become adorers of the Father “in spirit and truth” (Jn 4.23), we mature in an ever fuller union with Christ, we are ever more united to him, and—if one may use the expression—we are ever more in harmony with him.2
1. The teaching of Trent on the Mass and Eucharist has been ignored and even denied in some recent catechetical materials, but also has been firmly defended by the magisterium. See Eugene Kevane, Creed and Catechetics: A Catechetical Commentary on the Creed of the People of God (Westminster, Md.: Christian Classics, 1978), 141–52.
2. John Paul II, Dominicae cenae, sec. 5, 72 AAS (1980) 119–21; L’Osservatore Romano, Eng. ed., 24 March 1980, 6.