The sacraments are not just a matter of getting something from God, though many Christians emphasize that. Perhaps understandably–some of us think we have nothing substantive to offer back to God.
Baptism and Eucharist involve a mutual exchange, a spiritual communication if you will:
22. Incorporation into Christ, which is brought about by Baptism, is constantly renewed and consolidated by sharing in the Eucharistic Sacrifice, especially by that full sharing which takes place in sacramental communion. We can say not only that each of us receives Christ, but also that Christ receives each of us. He enters into friendship with us: “You are my friends” (Jn 15:14). Indeed, it is because of him that we have life: “He who eats me will live because of me” (Jn 6:57). Eucharistic communion brings about in a sublime way the mutual “abiding” of Christ and each of his followers: “Abide in me, and I in you” (Jn 15:4).
A “sacrament” is broadly defined as a sign instituted by Christ to give grace. If we accept the notion that Christ instituted the Church by means of that “New Covenant in my Blood,” and that all humanity now encounters Christ mainly through other people, the Church, then Christians indeed are a sacrament for the world.
John Paul II’s missionary impulse was likely born of this realization. Namely that we don’t exist for the individual relationship between believer and God. Nor is the Eucharist exclusively about cultivating a “chosen” community. The Eucharist provides fuel for the evangelical spirit.
By its union with Christ, the People of the New Covenant, far from closing in upon itself, becomes a “sacrament” for humanity, (Cf. Lumen Gentium 1.) a sign and instrument of the salvation achieved by Christ, the light of the world and the salt of the earth (cf. Mt 5:13-16), for the redemption of all. (Cf. Lumen Gentium 9.)The Church’s mission stands in continuity with the mission of Christ: “As the Father has sent me, even so I send you” (Jn 20:21). From the perpetuation of the sacrifice of the Cross and her communion with the body and blood of Christ in the Eucharist, the Church draws the spiritual power needed to carry out her mission. The Eucharist thus appears as both the source and the summit of all evangelization, since its goal is the communion of mankind with Christ and in him with the Father and the Holy Spirit. (Cf. Presbyterorum Ordinis 5. The same Decree, in No. 6, says: “No Christian community can be built up which does not grow from and hinge on the celebration of the most holy Eucharist”.)
Source and summit of evangelization. Not just the Christian life.
EdE 22 states the explicit connection between the Eucharist and evangelization and roots its case in a basic sacramental theology. Sacraments are for believers and non-believers alike. Including the Eucharist.