In preparing to preach today I was reflecting on how this feast day arrives as a sort of 'month's mind' Mass for Christmas Day. The gospel for the Mass of Christmas Day proclaims the prologue of St. John: the true Light, "which enlightens everyone, was coming into the world." Today Paul encounters that Light, and it changes the course of his whole life.
From there I was led to a reflection on how the major appearances of Paul (the man, that is) in the liturgy all have something to do with the Light. He first appears on the day after Christmas, at the martyrdom of Stephen, where St. Luke lets us know of his consent. The Light was not yet bright. Today, a month later in liturgical time, it's Brilliance is overwhelming.
Paul's own martyrdom comes to us on the feast of Peter and Paul, more or less on the octave day of the summer solstice. The Light has reached its peak, the gospel has been proclaimed to Jew and Gentile alike, and the great apostles go to their reward.