Thaddaeus was one of the 12 Apostles. It is believed that he was also known as Judas, son of James (not to be confused with Judas Iscariot, the man who betrayed Jesus). In some New Testament passages, the name Thaddaeus appears among the list of 12 Apostles. But in other New Testament passages, the name Judas (son of James) appears instead. In ancient times, a person could have two or three different names, such as a Greek-language name and a Hebrew name. And, sometimes people were known primarily by their occupational title.
The name Thaddaeus appears in the list of Apostles given in Matthew 10:3, between James, son of Alphaeus, and Simon the Zealot. In Mark 3:18, the name Thaddaeus appears, again, in the same placement. In Acts 1:13, however, a man named Judas (son of James) is listed below Simon. And in Luke 6:16, Judas (son of James), is listed again among the 12 Apostles, between Simon the Zealot and Judas Iscariot. The two names - Judas (son of James) and Thaddaeus - never appear in the same book, lending credence to the belief that they both refer to the same person.
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