...It is a fact that every liturgical celebration, “because it is an action of Christ the Priest and of His Body, which is the Church,” is a sacred action surpassing all others. Hence liturgical music, including that provided for the congregation, must be holy. As Pius X phrased it, sacred music must be “free from all that is profane, both in itself and in the method of performance.”
Fr. R. Skeris goes on to mention a few hymnals of note. At that time, however, the CMAA's Vatican II Hymnal had not been published, and it should be first on the current list.