The Nature of the Sacred Liturgy and Its Importance in the Church's Life - Part 7
Popular devotions of the Christian people are to be highly commended, provided they accord with the laws and norms of the Church, above all when they are ordered by the Apostolic See.
Devotions proper to individual Churches also have a special dignity if they are undertaken by mandate of the bishops according to customs or books lawfully approved.
But these devotions should be so drawn up that they harmonize with the liturgical seasons, accord with the sacred liturgy, are in some fashion derived from it, and lead the people to it, since, in fact, the liturgy by its very nature far surpasses any of them.
-Constitution on the Sacred Liturgy, Sacrosanctum Concilium # 13