In a passionate defense of Orthodox Christianity, Mark, Bishop of Ephesus, critiques those who have attempted to merge Latin rites with Orthodox beliefs, labeling them as "Greco-Latins." He argues that their teachings, particularly regarding the Holy Spirit's procession from the Father alone, diverge fundamentally from Orthodox doctrine. Mark condemns the Latin addition to the Creed as heretical and warns against the dangers of compromising faith for unity. He calls for a return to true Orthodoxy, emphasizing the necessity of rejecting heretical beliefs and practices while maintaining the integrity of the faith.