When is it appropriate to say the St. Michael Prayer following the Mass?

Q: I'm curious as to the appropriate practice of saying the St. Michael prayer either before the final blessing or after Mass. Is there a suggested practice to this powerful prayer as to when it should be said before the entire congregation?

A: I assume by "St. Michael prayer," you mean the prayer that usually begins: "St. Michael the Archangel, defend us in battle…" My own thought is that, since this is technically a devotional prayer and not part of the liturgy strictly speaking, if the St. Michael prayer is prayed in connection with a Mass, then it is most appropriate to do so after the final blessing. But depending on the customs of the local parish or community, there might potentially be a bit of "wiggle room" on this.

For some background, when we speak of the church's liturgical prayer, we mean the public and official prayers of the church. Liturgical prayer includes not only the Mass, but also the celebration of the other sacraments as well as the Liturgy of the Hours. Liturgical prayer by its very nature follows set written prayers and directions. This is in contrast with what we often call "mental prayer," where we privately speak to God in our own words.

Devotional prayers, like the rosary or the Divine Mercy chaplet, are a bit of a middle ground between private personal prayer and the liturgy. Devotional prayers usually do have their own specific words and structure, but they are not considered the public and official prayers of the church in a technical sense.

But the church still encourages devotional prayer! As we read in the Vatican II document "Sacrosanctum Concilium": "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."

Since liturgical prayer is the public and official prayer of the church, it can only be created, adapted or changed with the express approval of the Holy See in Rome. That is, the liturgy cannot be embellished or added to on a local level, even for pious motives. Because of this, it is generally considered illicit to incorporate devotional prayers -- even beautiful and well-established devotions -- into the actual celebration of Mass itself.

Saying the St. Michael prayer right after the final blessing neatly sidesteps the issue of mixing devotional prayer and liturgy, since after the final blessing any prayers being said are no longer in the context of the Mass.

But there are a few parts of the Mass where a limited degree of "improvisation" is expressly allowed. For example, the priest or deacon writes their own homily; the local community usually drafts or chooses their own words for the intercessions at the Prayer of the Faithful; and the General Instruction of the Roman Missal (GIRM) allows for "brief announcements" following the prayer after Communion (GIRM 90, 166, and 184). So I think including a devotional prayer during one of these more "free form" parts of the Mass could be acceptable.

Regarding the St. Michael prayer specifically, this prayer has an interesting history. It is said that Pope Leo XIII had a terrible vision where he saw Satan telling God he only needed a hundred years to destroy the church. Some versions of the story say that, in a scenario reminiscent of the Book of Job in the Old Testament, God permitted Satan to act, and the consequence was the horrors of the 20th century.

After he had this vision, Pope Leo XIII composed the St. Michael prayer for the sake of the church's spiritual protection. In 1886, he required that this prayer be said after every "low Mass" in the older ritual. Though the St. Michael prayer is no longer mandated in our post-Vatican II Mass, it can still be a beautiful and spiritually beneficial custom to pray it after the final blessing as a community.