After a year of preparation as novices, Br. Sebastian (Timothy) Kilburn, OSB, and Br. Isaac (Fernando) Acosta, OSB, professed temporary vows as monks of St. Gregory’s Abbey on September 3, 2026, the Solemnity of Pope St. Gregory the Great. The Rite of Monastic Profession was celebrated during Mass in the Abbey Church. Their vows of obedience, stability and conversion of life are valid for three years.
Born in Killeen, TX, Br. Sebastian is the son of Lt. Col. (Ret.) Ross and Mrs. Christy Kilburn of Flagstaff, AZ. Raised in a military family with his one sister and two brothers, Br. Sebastian has lived in several parts of the world and completed training as a sommelier before coming to St. Gregory’s. His first contact with the community was at Ft. Sill in southwestern Oklahoma where monks from the Abbey would often celebrate Mass.
Br. Isaac was born in Manilla, Philippines, to Dr. Melchor and Dr. Edna Acosta of Crowley, TX. He and his sister immigrated with their parents to the United States in 1999. He completed studies at Texas A&M School of Medicine with a residency in medical pathology. His first contact with St. Gregory's Abbey was at a Life Awareness Retreat in Dallas at which Vocation Director Fr. Simeon spoke.
Reflecting on this significant moment, Br. Sebastian explained what monastic profession means to him: “For me to profess vows is a response to love. It is an imitation of the all-encompassing Love of God in the act of the cross.” He added, “My vow of obedience is the work of my hands, stability is the way of my feet and conversion touches the depths of my heart. It is by taking up this cross that I am made free and whole because it is by taking up this cross that I am conformed to Love itself.”
Br. Isaac considers monastic profession to be his response to the question of his purpose and identity. He explains, “Why did God make me? To know the mercy of God in my life. My monastic profession is saying ‘yes’ to God’s will and purpose for me.” The journey toward his profession began on his first visit to the monastery. “My first visit was a bit surreal. I immediately knew that there is something here – a deeper experience of reality that drew me. It was something I simply knew without being able to analyze it with reason alone. I found here something visceral that goes beyond mere human wisdom.” Br. Isaac believes that this points to the place that monks have in the world today. “When people visit the monastery they recognize that there is something here that motivates us to live in this way. They want to know what this truth is. We monks are called to be a reflection of truth in the world and that the truth sought by all is a person – Jesus Christ.”