Translators may choose to call this book by its traditional title, "3 John" or "Third John." Or they may choose a clearer title, such as "The Third Letter from John" or "The Third Letter John Wrote." (See: [[rc://en/ta/man/translate/translate-names]])
The letter does not give the reader the name of the author. The author only identified himself as "the elder" (1:1). The letter was probably written by the Apostle John near the end of his life.
Hospitality was an important concept in the Ancient Near East. It was important to be friendly towards a foreigner or outsiders and provide help to them if they needed it. In 2 John, John discouraged Christians from showing hospitality to false teachers. In 3 John, John encouraged Christians to show hospitality to faithful teachers.
The author used the terms "brother" and "children" in a way that can be confusing. The scriptures often used the term "brothers" to refer to Jews. But in this letter, John used the word to refer to Christians. Also, John called some believers his "children." These are believers he taught to obey Christ.
John also used the term "Gentile" in a way that could be confusing. The scriptures often used the term "Gentile" to refer to people who are not Jews. But in this letter, John used the word to refer to those who did not believe in Jesus.