Tantum Ergo

The Tantum Ergo is sung at the very heart of Benediction of the Blessed Sacrament: as the faithful kneel and the priest incenses the exposed Host, the Church takes these words upon her lips just before the Sacred Host is lifted to bless the people. Like the O Salutaris that opens the rite, it is not a poem written on its own but the last two stanzas of a longer hymn — here the Pange Lingua Gloriosi, which St. Thomas Aquinas composed for Second Vespers of the Office of Corpus Christi.

The first stanza is a whole theology of the Eucharist in six lines. "Tantum ergo Sacraméntum venerémur cérnui" — "So great a Sacrament, therefore, let us venerate with bowed heads." The "ancient document" (antíquum documéntum) is the worship of the Old Covenant, the sacrifices and figures that now give way to the "new rite" (novo rítui) of the true and everlasting Sacrifice. And because the eyes see only bread, St. Thomas gives the soul its rule: "Præstet fides suppleméntum sénsuum deféctui" — let faith supply for the failure of the senses. What the eye cannot reach, faith adores.

The second stanza is a doxology to the Blessed Trinity — to the Father (Genitóri), to the Son begotten of Him (Genitóque), and to the Holy Spirit proceeding from both (Procedénti ab utróque). After it, the priest sings the versicle "Panem de cælo præstitísti eis" — "Thou hast given them bread from heaven" — and the prayer Deus, qui nobis, before raising the Host in silent blessing over the kneeling faithful.