III. When is the Liturgy Celebrated?

From The Catechism of the Catholic Church

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

PART TWO: THE CELEBRATION OF THE CHRISTIAN MYSTERY

SECTION ONE THE SACRAMENTAL ECONOMY
- CHAPTER TWO THE SACRAMENTAL CELEBRATION OF THE PASCHAL MYSTERY
  - Article 1 CELEBRATING THE CHURCH’S LITURGY
    - III. When is the Liturgy Celebrated?

From The Catechism of the Catholic Church – rosary.team