The Sacrament of the Holy Eucharist, the Body and Blood of Christ, is celebrated throughout the Church in several ways: first, on the altar through the Holy Sacrifice of the Mass; second, from that same altar in the Sacred Host brought by priests, deacons and lay extraordinary ministers to the sick in hospitals and to the homebound; third, again from that same altar, in prayer and adoration before the Tabernacle containing Sacred Hosts either reserved or exposed in the rite of Benediction of the Blessed Sacrament.

Through the words of the priest at Mass, recalling the Lord Jesus Christ’s own words at the Last Supper, unleaven bread and wine, the true fruit of the vine, is consecrated and transformed into the Body and Blood of Christ. This sacred action is called “transubstantiaton,” meaning the visible elements or “species” of the Eucharist — the bread and the wine — literally become the Body and Blood of Christ. How that actually happens is a mystery of the Catholic faith that has been believed and practiced since the very first Holy Thursday when Christ uttered the words “This is My Body, This is My Blood.”

Because the species remain sensible but the substance is transformed into Christ’s Body and Blood, Soul and Divinity, the mystery of the Holy Eucharist challenges the human mind in a way that only faith convinces us to believe. The ancient hymn of St. Thomas Aquinas urges “what our senses fail to fathom, let us grasp through faith’s consent.”

Why does the Catholic Church believe this? Because the Lord Jesus himself told us so. There is no better, no more compelling, no more necessary reason. And Catholics believe it as the central mystery of our faith or, as the Second Vatican Council calls it, “the source and summit of the Christian life (Lumen Gentium, 11).” The Catechism of the Catholic Church explains: “For in the Blessed Eucharist is contained the whole spiritual good of the Church, namely Christ himself ... (CCC, 1324).”

It is the same Body and Blood of Christ on the altar at Mass, in the Sacred Host brought to the sick and in the Tabernacle, hidden from view or exposed. It is not a “sign” or “symbol” of Christ like a crucifix or statue we display — it is the Lord Jesus Christ, True God and True Man, fully present.

Christ’s “Real Presence,” therefore, is the reason why we genuflect on our right knee or bow profoundly toward the Tabernacle when entering a Catholic Church and why we kneel during the Consecration at Mass. We also indicate Christ’s Real Presence in Church by a candle, usually in a red container, constantly lit and burning near the Tabernacle.

The Eucharist is Christ’s eternal gift of Himself to the Church — “I am with you always (Matthew 28:20)” — and the foundation of our Catholic faith and all that we do in the Church.

The Church has honored Christ’s Real Presence with a special, solemn feast after the Easter Season — Corpus Christi — for centuries. It has also been the theme of countless hymns, devotions and theological writings since that time as well — even before that time. But, in a very real sense, the Solemnity of the Body and Blood of Christ is celebrated at every Mass and during every Eucharistic commemoration.

In some Dioceses, following the Exposition and Benediction of the Blessed Sacrament, this concluding prayer of the “Divine Praises” is recited: “May the Heart of Jesus, in the Most Blessed Sacrament, be praised, adored and loved with grateful affection, at every moment, in all the Tabernacles of the world, even until the end of time. Amen.”