1174 The mystery of Christ, his Incarnation and Passover, which we celebrate in the Eucharist especially at the Sunday assembly, permeates and transfigures the time of each day, through the celebration of the Liturgy of the Hours, "the divine office."46 This celebration, faithful to the apostolic exhortations to "pray constantly," is "so devised that the whole course of the day and night is made holy by the praise of God."47 In this "public prayer of the Church,"48 the faithful (clergy, religious, and lay people) exercise the royal priesthood of the baptized. Celebrated in "the form approved" by the Church, the Liturgy of the Hours "is truly the voice of the Bride herself addressed to her Bridegroom. It is the very prayer which Christ himself together with his Body addresses to the Father.49
1175 The Liturgy of the Hours is intended to become the prayer of the whole People of God. In it Christ himself "continues his priestly work through his Church."50 His members participate according to their own place in the Church and the circumstances of their lives: priests devoted to the pastoral ministry, because they are called to remain diligent in prayer and the service of the word; religious, by the charism of their consecrated lives; all the faithful as much as possible: "Pastors of souls should see to it that the principal hours, especially Vespers, are celebrated in common in church on Sundays and on the more solemn feasts. The laity, too, are encouraged to recite the divine office, either with the priests, or among themselves, or even individually."51
1176 The celebration of the Liturgy of the Hours demands not only harmonizing the voice with the praying heart, but also a deeper "understanding of the liturgy and of the Bible, especially of the Psalms."52
1177 The hymns and litanies of the Liturgy of the Hours integrate the prayer of the psalms into the age of the Church, expressing the symbolism of the time of day, the liturgical season, or the feast being celebrated. Moreover, the reading from the Word of God at each Hour (with the subsequent responses or troparia) and readings from the Fathers and spiritual masters at certain Hours, reveal more deeply the meaning of the mystery being celebrated, assist in understanding the psalms, and prepare for silent prayer. The lectio divina, where the Word of God is so read and meditated that it becomes prayer, is thus rooted in the liturgical celebration.
1178 The Liturgy of the Hours, which is like an extension of the Eucharistic celebration, does not exclude but rather in a complementary way calls forth the various devotions of the People of God, especially adoration and worship of the Blessed Sacrament.
(Catechism of the Catholic Church/Part Two/Section One/Chapter Two)
FDLC - Liturgy of the Hours