The sacred liturgy is not some man-made rituals, nor is it like the ordinary prayer gatherings of the faithful. Whenever the Church celebrates the sacred liturgy, she is actualizing, here and now, the salvific plan of God (cf. Constitution on the Sacred Liturgy, 6)
Christ is always present in His Church, especially in the liturgical celebrations. He is present in the sacrifice of the Mass, not only in the person of His minister, but especially in the Eucharistic species. He is present in His word; he is also present whenever the Church prayers and sings (cf. ibid., 7).
The purpose of sacred music is the glory of God and the sanctification of the faithful. There are related norms and precepts deriving from ecclesiastical tradition and discipline (cf. ibid., 112).
“Sacred music increases in holiness to the degree that it is intimately linked with liturgical action ….” (ibid.)
Various kinds of sacred music and musical instruments are permitted to be adopted in liturgical celebrations, so long as they accord with the spirit of the liturgical action, the dignity of the church, and truly contribute to the edification of the faithful (cf. 116, 120).
“The texts intended to be sung must always be in conformity with Catholic doctrine; indeed they should be drawn chiefly from holy scripture and from liturgical sources” (ibid., 121).
“…the Mass is not an occasion for the preacher to address some issue completely unrelated to the liturgical celebration and its readings; or to do violence to the texts provided by the Church by twisting them to fit some preconceived idea.” (Congregation for Divine Worship and the Sacraments, Homiletic Directory, 29 June 2014, 6)
The important role of the homilist is to enable the congregation to realize that it is Christ who proclaims the Word of God to it and that the Word of God is fulfilled here and now. If the homilist wishes to refer to some personal experiences or some concrete instances, this should be done in such a way as to meet the actual needs of the faithful, with a view to facilitating them to be transformed by the Word of God and to put it into practice in their daily lives. (of. ibid., 4 – 11, 14)
Just like the “homily”, the “prayer of the faithful” should not be used to express views or stances on social issues or politics.