1. Ἰούδας. The name was common among Jews of the first century. The following identifications of this Judas (traditionally known in English as Jude) have been made:

(1) The overwhelming majority of scholars have understood this Judas to be Judas the brother of Jesus, who is mentioned in Matt 13:55; Mark 6:3; and Hegesippus (ap. Eusebius, Hist. Eccl. 3.19.1–20.6), though they are divided on whether Jude himself wrote the letter or a later writer wrote under his name. This view seems to give the best explanation of the two phrases by which Jude is described in v 1: “a servant of Jesus Christ and brother of James.” The brothers of the Lord were not known as “apostles” in the early Church, and so Jude’s authority to address his readers is expressed by the term “servant” rather than “apostle” (see below). The second phrase, which distinguishes this Judas from others of the same name, does so by mentioning his relationship to the only man in the primitive church who could be called simply “James” with no risk of ambiguity (see below). The only difficulty in this view is to understand why Jude is not here called “brother of the Lord” or “brother of Jesus Christ.” It is easier to explain this if the letter is authentic than if it is pseudepigraphal. Palestinian Jewish-Christian circles in the early church used the title “brother of the Lord” not simply to identify the brothers, but as ascribing to them an authoritative status, and therefore the brothers themselves, not wishing to claim an authority based on mere blood-relationship to Jesus, avoided the term (see below).

(2) Some older commentators (e.g. Calvin, Matthew Henry) identified the author as the apostle “Judas of James” (Luke 6:16; Acts 1:13: Ἰούδας Ἰακώβου). But (a) “Judas of James” naturally means “Judas son of James” rather than “Judas brother of James” (the latter translation, found in av, derives from the assumption that this apostle is the same person as Judas the Lord’s brother); (b)Jude does not call himself “apostle.”

(3) H. Koester (“ΓΝΩΜΑΙ ΔΙΑΦΟΡΟΙ,” HTR 58 [1965] 297) suggested that Jude is the apostle Thomas, who in Syrian Christian tradition was known as Judas Thomas or Judas “the twin” (Eusebius, Hist. Eccl. 1.13.11; Acts Thom.; Gos. Thom.; Thom. Cont. John 14:22 syc). Since Thomas is almost certainly not a personal name but a surname meaning “the twin,” the apostle must have had another name and it is possible that tradition has correctly preserved it as Judas. But this does not mean, as Koester thinks, that Judas “the twin” was the twin brother of Jesus and therefore identical with Judas the Lord’s brother. It is true that later tradition interpreted the surname “the twin” as meaning Jesus’ twin (Acts Thom. 31; 39; Thom. Cont. 138:4–8), but the idea was usually not that he was a blood-brother of Jesus but that he bore a close physical resemblance to Jesus (A. F. J. Klijn, “John xiv 22 and the Name Judas Thomas,” in Studies in John: presented to Professor Dr J. N. Sevenster [NovTSup 24; Leiden: E. J. Brill, 1970] 88–96) or that he was a kind of spiritual twin (cf. J. J. Gunther, “The Meaning and Origin of the Name ‘Judas Thomas,’ ” Mus 93 [1980] 113–148). Only at a late stage was Judas Thomas, Jesus’ “twin,” confused with Judas the blood-brother of Jesus.
This suggestion therefore cannot explain “brother of James,” and encounters the same difficulty as (2) in explaining why Jude does not call himself “apostle.”

Sidebottom (69, 79) adopted the same suggestion in arguing that Jude is a pseudonymous work of the early second century directed against gnostic heresy. Against the objection that Judas the Lord’s brother was too obscure a figure to be used as a pseudonym, Sidebottom points out that Judas Thomas was an important figure in gnostic literature (Gos. Thom.; Thom. Cont.). This argument, however, rests, like Koester’s, on the mistaken assumption that Judas Thomas was identified with Judas the Lord’s brother. Second-century Gnostics would not have recognized Judas Thomas under the description “Judas … brother of James.”

(4) Several scholars (Selwyn, Christian Prophets, 148; du Plessis, “Authorship,” developing an earlier argument by W. J. Fournier; Ellis, “Jude”; and cf. Plumptre, 85–86) have identified the author with Judas Barsabbas (Acts 15:22, 27, 32). But this Judas might be expected to distinguish himself from others of the same name by using his surname Barsabbas, rather than “brother of James,” even if this can be taken to refer to spiritual fraternity (du Plessis, “Authorship,” 197; for Ellis’s interpretation of “brother” here, see below).

(5) B. H. Streeter (The Primitive Church [London: Macmillan, 1929] 178–80) thought Jude was written by the third bishop of Jerusalem, whom the Apostolic Constitutions 7:46 called “Judas of James,” and that “brother” is a later addition to the text of Jude 1. This enabled him to date the letter in the early second century without regarding it as pseudonymous. Much earlier, Grotius had thought the author was Judas, the last Jewish bishop of Jerusalem according to Eusebius (Hist. Eccl. 4.5.3) (see Chase, DB(H) 2, 804 n.), who was perhaps the same man. These suggestions would be at all plausible only if the evidence for so late a date for Jude were compelling, but even then it would be hard to understand how the work of such an author could have come to be widely regarded as authoritative throughout the church by the end of the second century.

(6) Moffatt (244–46) thought the author was probably an otherwise unknown Judas, brother of an equally unknown James. This fails to take account of the fact that to identify oneself by reference to one’s brother, rather than one’s father, was extremely unusual and requires explanation. (The only theory which does explain it is that which identifies James as the James whom everyone knew.)

The traditional identification (1) remains the best. On whether the letter is an authentic writing of the Lord’s brother, or a pseudepigraphal letter written under his name, see Introduction.