Grace has been given to each of us according to the measure of Christ’s gifts to equip us for the work of ministry, that is, the building of the body of Christ. The Church commemorates today St. John Chrysostom, a man who became renowned for his eloquence as a preacher of the word of God (for which reason he was surnamed golden mouthed). But the eloquence of his thought was not limited to the spoken word alone. He was also a gifted writer whose work proved indispensable during doctrinal controversies. He defended the poor and sought for the reform of the clergy. Because of his love for the Church and truth of doctrine, he was twice exiled as head of his diocese by the royal opposition. He is the patron saint of preachers and of Istanbul (Constantinople). 
St. John Chrysostom is celebrated as one of the four great theologians (doctors) of the Eastern Church because he used his gifts and talents for the building of the Church. His defense of the true doctrine as taught by the Church arose from the conviction he had that as a member of the Church, it was his duty to promote the mission of the Church as an instrument of God’s salvation in the world. The independence of the Church from royal interference was a cause for which he was ready to give his life. 
In the First Reading, St. Paul writes to the members of the Ephesian Church reminding them that the Church stands upon their unselfish use of the variety of gifts with which God blesses every community. The Holy Spirit has gifted each member with a unique gift, and for the growth and unity of the community, these gifts have to be used for the benefit of all. This is the only way through which the Church can accomplish her mission of being the instrument of God’s salvation in the world. St. John Chrysostom certainly used his gift as both a pastor and teacher to defend the true teaching of the Church, the reason why the Church celebrates him on this day.