He initially refused the position of bishop, faced down an emperor, comforted a mother in her sorrows, and baptized the greatest philosopher of the first millennium. Who is he? None other than St. Ambrose of Milan, who became one of the first Doctors of the Church. When the position of bishop opened in Milan in A.D. 374 he was serving as governor of the province. He was not a baptized Christian, but the people acclaimed him bishop anyway, whereupon he ran away to hide. Once, the emperor heard about the election, he affirmed it and Ambrose accepted, being baptize and ordained within the week.
However, once he became bishop, he invested his whole life into serving the people, correcting the heresy of Arianism, teaching orthodox theology in great homilies, and guiding the liturgy of Milan, which is called the Ambrosian Rite and still used today. He confronted Emperor Theodosius in 390 after the emperor allowed/ordered the massacre of citizens of Thessalonica. St. Ambrose required the emperor to do penance before he could receive the Eucharist. Theodosius did so. According to legend, he also comforted St. Monica when she came to him in tears: "The child of those tears shall never perish." That child was St. Augustine, who came to Milan to listen to St. Ambrose's sermons. They gave him the intellectual grounding he needed to convert to Christianity, with St. Ambrose baptizing him.
St. Ambrose responded to God's call by giving his life over to God. We, too, are called to give our lives to God. We are called live our lives as disciples of Jesus: loving, witnessing, serving, praying, worshiping, and working to bring about the Kingdom of God here on earth in our families, jobs, and associations. We are called to the greatness of holiness!