The Nature of the Sacred Liturgy and Its Importance in the Church's Life - Part 6
But in order that the liturgy may be able to produce its full effects, it is necessary that the faithful come to it with proper dispositions, that their minds should be attuned to their voices, and that they should cooperate with divine grace lest they receive it in vain (2 Cor. 6:1). Pastors of souls must therefore realize that, when the liturgy is celebrated, something more is required than the mere observation of the laws governing valid and licit celebration; it is their duty also to ensure that the faithful take part fully aware of what they are doing, actively engaged in the rite, and enriched by its effects.
The spiritual life, however, is not limjted solely to participation in the liturgy. The Christian is indeed called to pray with his brethren, but he must also enter into his chamber to pray to the Father, in secret (Matt. 6:6); yet more, according to the teaching of the Apostle, he should pray without ceasing (1 Thess. 5:17). We learn from the same Apostle that we must always bear about in our body the dying of Jesus, so that the life also of Jesus may be made manifest in our bodily frame (2 Cor. 4:10-11). This is why we ask the Lord in the sacrifice of the Mass that, "receiving the offering of the spiritual victim," he may fashion us for himself "as an eternal gift".
-Constitution on the Sacred Liturgy, Sacrosanctum Concilium # 11-12