The Eucharist is both complex and simple. Complexity is reflected in the five reasons listed by Trent for its institution by Jesus. But the Eucharist also involves another complexity. Like Jesus’ life, this sacrament—as well as the other sacraments by their relationship to it—is a revelatory sign communicating God’s truth and love, and also a human response of sacrifice in thanksgiving. Jesus acts in the Mass but so do we, with him offering to the Father both him and ourselves united with him. For all its complexity, however, the Eucharist is also simple. It is not a multiplicity of unrelated purposes and actions but the expression of the divine-human communion of love—God’s self-communication to us and our response through, with, and in Jesus.
Jesus’ fundamental sacrifice is his obedience to the Father’s will. At the Last Supper he empowers the apostles and priests of all times to make this sacrifice present in the Mass. All Christians share in the universal priesthood of the faithful, since all are called to offer spiritual sacrifices; and, if done in the Spirit, all the activities of life become such sacrifices. But it is above all in the celebration of the Eucharist that these are offered to the Father in union with Jesus. The living of Christian life as a sharing in the sacrifice of Christ thus prepares for and flows from the Eucharist.
Our communion with Jesus has three inseparable but distinct aspects: sharing by adoption in his divine life, which begins in baptism; sharing in his revelatory life, for which we are commissioned in confirmation; and bodily union with him and enlivening by his resurrection life, effected by the Eucharist. In the Eucharist we consume Jesus’ living, bodily self, while he causes our bodily selves to come alive with his glorious, resurrected life. This communion maintains and perfects the sharing in divine life and cooperation in human action which also unite us with him.
In ordinary human experience, the more one gives a person, the more one loves him or her, and the more one loves, the more one wishes to give. This “virtuous circle” is present also in the Eucharist. We bring gifts representing ourselves; this offering leads to Jesus’ offering of himself, in which we share while at the same time offering ourselves united and transformed in him. The many reasons for leading a good Christian life are gathered up in this virtuous circle of love: God has given us everything, and we must thank him with, through, and in Jesus; the more we do, the more we love him, and the more we love him, the more perfectly we must live to make a better gift.
Still, why suppose that if we offer our lives to God, he will accept? The answer is found in Jesus. His gift is accepted; his resurrection in glory is God’s acceptance of it. In the Eucharist, we are united to Jesus—Jesus as he is, risen in glory. Since we receive his resurrection life in the Eucharist, we have in this sacrament not simply a promise of heavenly glory but a beginning of it.
As the sacrament of unity with Jesus, the Eucharist is also the sacrament by which the unity of the Church is built up and sustained. By making us one with him it establishes a bond of communion among us. This bond is ecclesial communion, constitutive of the Church. Preaching the gospel, faith, and baptism also constitute the Church, but in an initial, incomplete manner which the Eucharist brings to fullness and completion.
The Eucharist is extended throughout the day by the Liturgy of the Hours. All one’s life is to be lived as preparation of the gift one offers in the Eucharist with, through, and in Jesus and as execution of the dismissal mandate at Mass to love and serve the Lord. But Christian life must be formed and structured by appropriate prayer, and the Liturgy of the Hours is the common act of prayer provided by the Church for shaping life as an extension of the Eucharist.
For most Christians, too, the Eucharist is extended into their basic personal relationships by the sacrament of matrimony. The self-giving, love, and service of marriage and family life prepare the gift to be offered in the Eucharist and carry out its mandate. The marital relationship enjoys the status of a sacrament because, as the union of two in one flesh, the marital covenant symbolizes the unity of Jesus with the Church—the unity accomplished in us by the Eucharist. In other words, the marital relationship is a sacrament because of its intrinsic relationship to the Eucharist, as a sign of what the Eucharist realizes.