Although no longer included within the Carmelite calendar, the feast of St. Hilarion is still listed on October 21st in the 2004 Roman Martyrology. St. Hilarion died around 371 AD.
Omnipotent and eternal God! who art always and everywhere admirable in the merits of Blessed Hilarion, Thy Confessor; we beseech Thy clemency that even as Thou hast raised him to a high degree of glory, so we may be helped by his prayers to obtain Thy mercy. Through our Lord Jesus Christ, Your Son Who lives and reigns with You in the unity of the Holy Spirit one God, forever and ever. Amen.
Hilarion was born at Tabatha in Palestine of heathen parents. He was sent to Alexandria to pursue his studies, and there became noted for his character and talent. After he had embraced the religion of Jesus Christ he grew rapidly in faith and love. He was often in the church, and fasted and prayed constantly. Despising the allurements of pleasure, he rose above all earthly desires. He took not pleasure in the frantic excitement of the race-course, the bloody combats of the arena, nor in the license of the theatre. His whole heart was in the services of the Church.
The name of Anthony was then celebrated in Egypt, and Hilarion journeyed into the desert to see him. He spent two months with Anthony, and learned perfectly his way of life. Finding his parents dead on his return, he distributed his inheritance amongst the poor and went back into the desert, though he was not then fifteen years old. There be built a little hut, scarcely large enough to hold him, and slept upon the ground. He wore a sack which he neither washed nor changed from the time when he first put it on, for he said that it was idle to strive after cleanliness when wearing haircioth.
He spent a great part of his time in reading and meditating on the sacred writings. A few figs and the juice of herbs served him for food, and even these he ate not before sunset. His chastity and humility were wonderful. By the help of these and his other virtues, he conquered various horrible temptations of the devil, and drove many demons from the bodies of men, in different parts of the world. After he had built many monasteries and had become known by the fame of his miracles, he fell ill at the great age of eighty years. When illness had brought him to the last extremity he exclaimed in his death’s agony: “Go forth, my soul, what dost thou fear? Go forth, why dost thou hesitate? Thou hast served Christ for nearly seventy years, and dost thou fear to die?” With these words he breathed out his soul.
Taken from the book “Saints of Carmel” (BOSTON: JOHN CASHMAN & CO., 1896).