Q: Toward the end of Eucharistic Prayer III there is an option, after the invocation of the Blessed Mother, St Joseph, the Apostles and Martyrs, to invoke “the Saint of the day or Patron Saint.” When a Sunday takes precedence over a Memorial or a Feast, may that Saint be used in this portion of Eucharist Prayer III event though the Mass being celebrated isn’t for the Memorial or Feast?
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A: I would say yes, though I can’t prove it. The concept behind that section of Prayer III was to provide a more focused, shorter list of saints than the ones in Prayer I. Inserting the name on a Sunday does no harm to that ideal.