Pope Leo XIV ordains a priest in St. Peter’s Basilica on the solemnity of the Most Sacred Heart of Jesus, Friday, June 27, 2025. / Credit: Daniel Ibáñez/CNA

Archbishops wear the pallium they received from Pope Francis in St. Peter’s Basilica, June 29, 2014. / Credit: Daniel Ibáñez/CNA

Top, left to right: St. Catherine of Siena, St. John Paul II, Sacred Heart of Jesus, St. Margaret Mary Alacoque, St. Francis de Sales. Bottom, left to right: St. John Henry Newman, St. Gertrude of Helfta, St. Thérèse of Lisieux, and St. Thomas Aquinas. / Credit: Brooklyn Museum, Public domain, via Wikimedia Commons; Gov.pl, CC BY 3.0 PL, via Wikimedia Commons; Leiloeira São Domingos, Public domain, via Wikimedia Commons; Corrado Giaquinto, Public domain, via Wikimedia Commons; Giovanni Battista Lucini, Public domain, via Wikimedia Commons; Herbert Rose Barraud, Public domain, via Wikimedia Commons; Public domain via Wikimedia Commons; Céline Martin, CC0, via Wikimedia Commons; Carlo Crivelli, Public domain, via Wikimedia Commons

Friends, this year, the feast of Saints Peter and Paul falls on a Sunday, and I want to spend some time reflecting especially on Saint Peter. Around the year 64, Shimon Bar Yonah, a fisherman from Galilee, was put to death brutally in the Circus of Nero. But while the Roman Empire is long gone and the successor of Nero doesn’t exist, the empire of this fisherman, Peter the Apostle, is everywhere, and in May, his 266th successor walked out onto the loggia of Saint Peter’s Basilica, built over the very spot where he was buried. 

Friends, every year we have Trinity Sunday followed by today’s wonderful Solemnity of Corpus Christi—two of the highest theological mysteries of our faith, the Trinity and the Eucharist, back to back. As we reflect today on the Body and Blood of Jesus, I want to explore the deep connection between temple sacrifice, the altar of the cross, and the Mass.

Friends, today is Trinity Sunday—one of my favorite feast days of the year because I can put my old theologian’s cap on. Looking first at one of the greatest of the medieval theologians, Saint Bonaventure, and then at maybe the greatest figure in Western theology, Saint Augustine, I’d like to reflect with you on the dynamics of the Trinitarian life—the very matrix into which we’re inserted through baptism.