Deus, in adiutorium meum intende

These words form the introductory prayer to every Hour of the Roman, Ambrosian, and monastic Breviaries, except during the last three days of Holy Week, and in the Office of the Dead.

Tradition says that Benedict of Nursia introduced this custom into the monastic Office, heavily influenced by the writings of Saint John Cassian.

In placing this supplication at the beginning of every canonical hour, the Catholic Church implores the assistance of God against distractions in prayer.

In the Roman Rite, the "Deus, in adiutorium" is preceded at Matins by the "Domine, labia mea aperies" ("Open Thou, O LORD, my lips), whilst in the monastic breviary, the order is reversed.

In monasteries, Prime was finished immediately after the prayer: "Domine, Deus omnipotens"; then the monks went from the choir to the chapter-room, where the Martyrology was read, and the day's work was given out; before dispersing to their several occupations they sang three times the "Deus, in adjutorium", to emphasize the union of prayer and labour.