Thou, who at Thy first Eucharist didst pray

“Thou, Who at Thy First Eucharist Didst Pray” is a Eucharistic hymn by William H. Turton, written in 1881. Turton was an Anglican hymn writer whose hymns were published in collections under the title A Few Hymns Written by a Layman. Hymnary records this hymn as one of his hymns concerning Christian unity. It was used at St. Mary Magdalene's, Munster Square, London, on June 22, 1881, at the anniversary service of the English Church Union. The hymn was intended to be sung after the Agnus Dei at a choral celebration.

The hymn draws its central theme from Christ's prayer in John 17, especially His prayer that His disciples might be one. The opening stanza looks back to the first Eucharist and to the prayer of Jesus before His death. The refrain expresses the desire that believers may become “one Bread, one Body,” drawing upon the biblical imagery of 1 Corinthians 10:16-17, where Paul connects participation in the bread and cup with the unity of the body of Christ. The Eucharist is therefore presented in the hymn not merely as a sacred observance, but as a reminder of the unity Christ desires among His people.

The later stanzas extend this prayer for unity beyond the present life. The worshiper asks that Christians may be joined together in peace and love, and ultimately be united with the whole Church above. The hymn concludes by looking toward the perfect unity of believers with the Trinity. This gives the hymn a strong ecclesial and eschatological dimension, connecting Holy Communion with Christian fellowship, reconciliation, and the hope of complete unity in God's presence.

Hymnary records the meter as 10.10.10.10.10.10 and lists several tunes associated with the text, including SONG I, UNDE ET MEMORES, and SACRAMENTUM UNITATIS. In The Book of Praise, the tune SONG I is identified as a composition by Orlando Gibbons. The hymn has consequently appeared in Anglican, Protestant, and ecumenical hymnals in forms adapted for Eucharistic and Communion worship.