(Gr. eucharistia, thanksgiving).
The name given to the Blessed Sacrament of the Altar its twofold aspect of sacrament and Sacrifice of Mass, and in which Jesus Christ is truly present under the bread and wine. Other titles are used, such as "Lord's Supper" (Coena Domini), "Table of the Lord" (Mensa Domini), the "Lord's Body" (Corpus Domini), and the "Holy of Holies" (Sanctissimum), to which may be added the following expressions, and somewhat altered from their primitive meaning: "Agape" (Love-Feast), "Eulogia" (Blessing), "Breaking of Bread", "Synaxis" (Assembly), etc.; but the ancient title "Eucharistia" appearing in writers as early as Ignatius, Justin, and Irenæus, has taken precedence in the technical terminology of the Church and her theologians. The expression "Blessed Sacrament of the Altar", introduced by Augustine, is at the present day almost entirely restricted to catechetical and popular treatises. This extensive nomenclature, describing the great mystery from such different points of view, is in itself sufficient proof of the central position the Eucharist has occupied from the earliest ages, both in the Divine worship and services of the Church and in the life of faith and devotion which animates her members.
The Church honors the Eucharist as one of her most exalted mysteries, since for sublimity and incomprehensibility it yields in nothing to the allied mysteries of the Trinity and Incarnation. These three mysteries constitute a wonderful triad, which causes the essential characteristic of Christianity, as a religion of mysteries far transcending the capabilities of reason, to shine forth in all its brilliance and splendor, and elevates Catholicism, the most faithful guardian and keeper of our Christian heritage, far above all pagan and non-Christian religions.
The organic connection of this mysterious triad is clearly discerned, if we consider Divine grace under the aspect of a personal communication of God. Thus in the bosom of the Blessed Trinity, God the Father, by virtue of the eternal generation, communicates His Divine Nature to God the Son, "the only begotten Son who is in the bosom of the Father" (John, i, 18), while the Son of God, by virtue of the hypostatic union, communicates in turn the Divine Nature received from His Father to His human nature formed in the womb of the Virgin Mary (John, i, 14), in order that thus as God-man, hidden under the Eucharistic Species, He might deliver Himself to His Church, who, as a tender mother, mystically cares for and nurtures in her own bosom this, her greatest treasure, and daily places it before her children as the spiritual food of their souls. Thus the Trinity, Incarnation, and Eucharist are really welded together like a precious chain, which in a wonderful manner links heaven with earth, God with man, uniting them most intimately and keeping them thus united. By the very fact that the Eucharistic mystery does transcend reason, no rationalistic explanation of it, based on a merely natural hypothesis and seeking to comprehend one of the sublimest truths of the Christian religion as the spontaneous conclusion of logical processes, may be attempted by a Catholic theologian.
The modern science of comparative religion is striving, wherever it can, to discover in pagan religions "religio-historical parallels", corresponding to the theoretical and practical elements of Christianity, and thus by means of the former to give a natural explanation of the latter. Even were an analogy discernible between the Eucharistic repast and the ambrosia and nectar of the ancient Greek gods, or the haoma of the Iranians, or the soma of the ancient Hindus, we should nevertheless be very cautious not to stretch a mere analogy to a parallelism strictly so called, since the Christian Eucharist has nothing at all in common with these pagan foods, whose origin is to be found in the crassest idol- and nature-worship. What we do particularly discover is a new proof of the reasonableness of the Catholic religion, from the circumstance that Jesus Christ in a wonderfully condescending manner responds to the natural craving of the human heart after a food which nourishes unto immortality, a craving expressed in many pagan religions, by dispensing to mankind His own Flesh and Blood. All that is beautiful, all that is true in the religions of nature, Christianity has appropriated to itself, and like a concave mirror has collected the dispersed and not infrequently distorted rays of truth into their common focus and again sent them forth resplendently in perfect beams of light.
It is the Church alone, "the pillar and ground of truth", imbued with and directed by the Holy Spirit, that guarantees to her children through her infallible teaching the full and unadulterated revelation of God. Consequently, it is the first duty of Catholics to adhere to what the Church proposes as the "proximate norm of faith" (regula fidei proxima), which, in reference to the Eucharist, is set forth in a particularly clear and detailed manner in Sessions XIII, XXI, and XXII of the Council of Trent. The quintessence of these doctrinal decisions consists in this, that in the Eucharist the Body and Blood of the God-man are truly, really, and substantially present for the nourishment of our souls, by reason of the transubstantiation of the bread and wine into the Body and Blood of Christ, and that in this change of substances the unbloody Sacrifice of the New Testament is also contained. These three principle truths -- Sacrifice, Sacrament, and Real Presence -- are given a more detailed consideration in the following articles: