Diotrephes is a figure mentioned in the New Testament, specifically in the book of 3 John. He is described as a leader in a Christian community who rejected the authority of the apostle John and refused to welcome traveling missionaries. His behavior is characterized by pride and a desire for prominence within the church. In 3 John 1:9-10, John criticizes Diotrephes for spreading malicious gossip and for not only refusing to accept the missionaries but also expelling those who did. This account serves as a warning against arrogance and the importance of hospitality within the Christian faith.