This Mass “For Chastity” is a new one since 1998/2002; no Lectionary readings are assigned to it. No proper antiphons are given in the Missal. The only clues we have for liturgy preparation are with the prayers for Mass. And these are three:
Purify our hearts, O Lord, by the heavenly fire of the Holy Spirit, that we may serve you with a chaste body and please you with a pure heart.
The prayer over the offerings makes reference to offering sacrifice “in full freedom and with a pure mind.” After Communion, we pray:
… may our heart and our body flourish anew by a keen sense of modesty and renewed chastity, …
The prayers cover the human basics: body, mind, and heart. They suggest that chastity enables good and fruitful service of God. It would seem that’s something to sing about. My suggestions would be Psalm 104 or 128 from the Old Testament. 1 Corinthians 13 from the New. If we are singing about chastity as assisting the service of God, Psalms 16, 40 or 116.
I am curious about the inclusion of a new Mass for a need of occasion and not providing any Scriptural back-up for it. Is chastity a serious issue or not? Does it impact lay people, vowed religious, and clergy? In each case the issues are a bit different. The whole aspect seems a missed opportunity to me, something of a mystery as well.
Some years ago, we blogged on Masses And Prayers For Various Needs And Occasions. In the GIRM, sections 368-378 cover the universal regulations on their use. You can check our brief comments here and here and here. The USCCB’s unannotated text on the matter is here.