Office of Divine Worship

"While the liturgy daily builds up those who are within into a holy temple of the Lord, into a dwelling place for God in the Spirit, to the mature measure of the fullness of Christ, at the same time it marvelously strengthens their power to preach Christ, and thus shows forth the Church to those who are outside as a sign lifted up among the nations under which the scattered children of God may be gathered together, until there is one sheepfold and one shepherd."

- Sacrosanctum concilium (Constitution on the Sacred Liturgy), no. 2