Possible Clues:

• Against bogus responses
• Saint penning revolutionary religious church music
• Opposing inauthentic sort of singing in church
• Saint welcomes uplifting religious music in church
• Alternate singing apparently opposed to fake
• Call-and-response singing
• For the real thing?
• Singing by turns, for real?
• Whose plays likely to figure in this lexicon?
• Singing that's for real?