Liturgy of the hours or Divine Office
The Liturgy of the Hours consists primarily of psalms supplemented by hymns and readings. Together with the Mass, it constitutes the official public prayer life of the Church. Upon ordination to any of the Holy Orders, the daily recitation of the Liturgy of the Hours becomes a canonical obligation. Priests are required by canon law to pray the entire Liturgy of the Hours each day while deacons are required to pray the morning and evening hours. The Liturgy of the Hours also forms the basis of prayer within Christian monasticism.
The practice among religious communities varies according to their rulesand constitutions. The Second Vatican Councilalso exhorted the Christian laity to take up the practice, and as a result, many lay people have begun reciting portions of the Liturgy of the Hours.
The Liturgy of the Hours, along with the Eucharist, has formed part of the Catholic Church's public worship from the earliest times. Christians of both Eastern and Western traditions (including the Roman Catholic, Eastern Orthodox, Oriental Orthodox, and Anglican churches) celebrate the Liturgy of the Hours under various names.
Within Roman Catholicism, the Liturgy of the Hours is contained within the Roman Breviary. In Greek the corresponding services are found in the Ὡρολόγιον (Horologion), meaning Book of Hours. Within Anglicanism, the Liturgy of the Hours is contained within the book of Daily Prayer of Common Worship and Book of Common Prayer.