The prayer hours of the Christian Church find their origins in the ancient prayers of the Jewish Synagogue, the prayer patterns of the apostles, the early Eucharist, and the monasteries. The prayer of the Church, the Divine Office, is not something left to monks, nuns, or clergy alone, but is the foundation of daily Christian life, the tradition entrusted to the Church (2 Thess. 2.15; 1 Cor. 11.2) to “hold fast.” As Prosper of Aquitaine stated in his defense against the Pelagians, Lex Orandi, Lex Credendi: the rule of our prayer is the rule of our belief. In the Office we read and pray from Scripture, from the writings of the Holy Fathers, and from the legend of the lives of the Saints; we sing canticles, and pray for the Church, the living and the dead, and for each other.
The heart of the Office is in the singing/saying of Psalms and the Lord’s Prayer. The Psalms attest to the Jewish cycle of prayer, three times a day, or seven times, and at midnight. The New Testament speaks of the Apostles going to Temple for prayer at the third hour, the sixth hour, and the ninth hour. We read of Jesus praying the Psalms, and clearly he knew them well, as he quoted them during his last moments on the cross. The Didache, an early Christian rule, speaks of Christians praying the Lord’s Prayer three times a day. In the cathedral tradition of Cranmer and King Edward VI we say Morning and Evening Prayer. In Cranmer’s Morning Prayer we have a mix of the midnight, morning, and first monastic hours, and in Evensong, or Evening Prayer, we have Vespers and Compline. Cranmer’s name for these two services was “The Book of Common Prayer,” by which name we now commonly call our entire service book. (Cranmer’s name for his first service book in English, before the inclusion of the Ordinal and Articles of Religion, was, The book of the common prayer and administration of the Sacraments, and other rites and ceremonies of the Church after the use of the Church of England.)
Whenever the Church prays, we offer ourselves to God, a sacrifice of praise of thanksgiving.