... the whole congregation in accordance with the rules of the Liturgy, either answer the priest in an orderly and fitting manner, or sing hymns suitable to the different parts of the Mass, or do both, or finally in High Masses when they answer the prayers of the minister of Jesus Christ and also sing the liturgical chant” (Mediator Dei, §105) (emphasis added).

'The chief aim of these methods of participation is “to foster and promote the people’s piety and intimate union with Christ and His visible minister and to arouse those internal sentiments and dispositions which should make our hearts become like to that of the High Priest of the New Testament” (Mediator Dei, §106).