As a young man, in his mid-twenties, he embraced the religious life, entering the Ukrainian Order of Saint Basil, commonly known as the Basilians. As a monk, he distinguished himself by his extraordinary spirit of prayer, penance, and mortification. He frequently went barefoot, even during the bitter cold of winter, and was content with the poorest of food. His life was one of simplicity and self-denial, and his holiness soon became evident to those who knew him. He was eventually ordained a priest and devoted himself to preaching, teaching, and encouraging the faithful in their Catholic traditions.
In 1618, after years of religious life, Josaphat was appointed Archbishop of Polotsk. He undertook his episcopal responsibilities with great zeal, seeking to strengthen the spiritual life of his people and, above all, to restore unity between the Eastern Christians and the See of Rome. He worked tirelessly to promote the union of the Ukrainian Church with the successor of St. Peter, believing that the divisions among Christians contradicted the unity for which Christ had prayed. His efforts included the reform of the clergy, the restoration of neglected churches, and the instruction of the faithful.
His work, however, aroused fierce opposition among those Orthodox Christians who rejected union with Rome. They regarded his efforts as a threat to their independence, and hostility against him grew increasingly bitter. Josaphat was well aware that his life was in danger, but he refused to abandon his mission. He believed that Christian unity was worth every sacrifice, even the sacrifice of his own life.
In November of 1623, while visiting his diocese at Vitebsk, his enemies organized a violent attack upon the residence where he was staying. Several of his attendants were assaulted, and some were killed. Rather than flee or seek to defend himself, Josaphat went calmly toward the angry mob and asked why they had come against him. With remarkable humility and courage, he said, "If you have something against me, see, here I am." The crowd shouted, "Kill the papist!" and rushed upon him with their weapons. He was struck with an axe and killed, giving his life in witness to the unity of Christ's Church.
His body was thrown into the river, but it remained miraculously afloat and was recovered. The circumstances surrounding his death and the testimony of his holiness strengthened the devotion of the faithful. Even some of those responsible for his murder eventually repented of their crime and returned to Catholic unity.
St. Josaphat was canonized in 1867, becoming the first Eastern Catholic saint formally canonized by Rome. His martyrdom remains a powerful testimony that the unity of Christ's Church is not merely an earthly aspiration, but a sacred gift for which Christians must pray and work with charity, courage, and perseverance.
Stir up in thy Church, we pray, O Lord, the Spirit that filled Saint Josaphat: that, as he laid down his life for the sheep; so through his intercession we, too, may be strengthened by the same Spirit and not fear to lay down our life for our brethren; through Jesus Christ thy Son our Lord, who liveth and reigneth with thee, in the unity of the Holy Spirit, ever one God, world without end. Amen.