The laity may oblige themselves to pray the Liturgy of the Hours or part of it by a personal vow. Within the Latin Church, the lay faithful 'are encouraged to recite the divine office, either with the priests, or among themselves, or even individually,' though there is no obligation for them to do so. Consecrated virgins take the duty to celebrate the liturgy of hours with the rite of consecration. The constitutions of religious institutes generally oblige their members to celebrate at least parts and in some cases to do so jointly ('in choir'). Prayer of the Divine Office is an obligation undertaken by priests and deacons intending to become priests, while deacons intending to remain deacons are obliged to recite only a part. The chant or recitation of the Divine Office therefore forms the basis of prayer within the consecrated life, with some of the monastic or mendicant orders producing their own permutations of the Liturgy of the Hours and older Roman Breviary. Christians of both Western and Eastern traditions (including the Latin Catholic, Eastern Catholic, Eastern Orthodox, Oriental Orthodox, Assyrian, Lutheran, Anglican, and some other Protestant churches) celebrate the canonical hours in various forms and under various names. Together with the Mass, it constitutes the public prayer of the Church. The Liturgy of the Hours, like many other forms of the canonical hours, consists primarily of psalms supplemented by hymns, readings, and other prayers and antiphons prayed at fixed prayer times. Before 1971, the official form for the Latin Church was the Breviarium Romanum, first published in 1568 with major editions through 1962. The Liturgy of the Hours forms the official set of prayers 'marking the hours of each day and sanctifying the day with prayer.' The term 'Liturgy of the Hours' has been retroactively applied to the practices of saying the canonical hours in both the Christian East and West–particularly within the Latin liturgical rites–prior to the Second Vatican Council, and is the official term for the canonical hours promulgated for usage by the Latin Church in 1971. The Liturgy of the Hours ( Latin: Liturgia Horarum) or Divine Office (Latin: Officium Divinum) or Opus Dei ('Work of God') are a set of Catholic prayers comprising the canonical hours, often also referred to as the breviary, of the Latin Church.

Cistercian monks praying the Liturgy of the Hours in Heiligenkreuz Abbey

Divine office volume 2