The Promotion of Liturgical Instruction and Active Participation
Mother Church earnestly desires that all the faithful should be led to that fully conscious, and active participation in liturgical celebrations which is demanded by the very nature of the liturgy. Such participation by the Christian people as "a chosen race, a royal priesthood, a holy nation, a redeemed people" (1 Pet. 2:9; cf. 2:4-5), is their right and duty by reason of their baptism.
In the restoration and promotion of the sacred liturgy, this full and active participation by all the people is the aim to be considered before all else; for it is the primary and indispensable source from which the faithful are to derive the true Christian spirit; and therefore pastors of souls must zealously strive to achieve it, by means of the necessary instruction, in all their pastoral work.
-Constitution on the Sacred Liturgy, Sacrosanctum Concilium # 14