Worship and devotion
Prayer
2720: The Church invites the faithful to regular prayer: daily prayers, the Liturgy of the Hours, Sunday Eucharist, the feasts of the liturgical year.
2722: Vocal prayer, founded on the union of body and soul in
human nature, associates the body with the interior prayer of the heart,
following Christ's example of praying to his Father and teaching the Our Father
to his disciples.
2700: Through his Word, God speaks to man. By words, mental or vocal, our prayer
takes flesh. Yet it is most important that the heart should be present to him to
whom we are speaking in prayer: "Whether or not our prayer is heard depends not
on the number of words, but on the fervour of our souls."
2704: Because it is external and so thoroughly human, vocal prayer is the form
of prayer most readily accessible to groups. Even interior prayer, however,
cannot neglect vocal prayer. Prayer is internalized to the extent that we become
aware of him "to whom we speak". Thus vocal prayer becomes an initial form of
contemplative prayer.
http://www.vatican.va/archive/ccc_css/archive/catechism/p2s2c1a3.htm