Hastings' Dictionary of the Bible 
THADDÃ†US . This is the name of one of the Twelve Apostles as given in Matthew 10:3 , Mark 3:18 . He is doubtless to be identified with the ‘ Judas [son] of James,’ who appears in the Lukan lists ( Luke 6:18 , Acts 1:13; so RV [Note: Revised Version.] , but AV [Note: Authorized Version.] renders ‘ brother of James’), and with the ‘Judas, not Iscariot,’ of John 14:22 , though some Syrian writers have made this last Judas to be the same as the Apostle Thomas (syr sin reads here ‘Thomas,’ syr cur reads ‘Judas Thomas’), Thomas being confessedly only a surname, ‘the Twin.’
In all four lists ThaddÃ¦us (or Judas) comes next to Simon the CananÃ¦an or Zealot, and may not improbably have been his brother or intimate friend (cf. the variant ‘Judas Zelotes’ in Matthew 10:3 , noted below). It is the opinion of almost all modern scholars that neither is to be identified with any of the Brethren of our Lord, though Dom Chapman has lately published an elaborate argument to the contrary ( JThSt [Note: ThSt Journal of Theological Studies.] vii. 412).
Instead of, or in addition to, ‘ThaddÃ¦us,’ we find the variant LebbÃ¦us . In Mark 3:13 , Codex Bezae (D [Note: Deuteronomist.] ) and some Old Latin MSS have ‘LebbÃ¦us’; but all the best authorities, including syr sin (Syr cur is wanting here), have ‘ThaddÃ¦us,’ and this is doubtless right. In Matthew 10:3 the oldest Greek MSS ( × B), the Vulgate, the Coptic, and some Old Latin MSS have ‘ThaddÃ¦us,’ while D [Note: Deuteronomist.] , supported by the valuable Old Latin k and some other MSS, has ‘LebbÃ¦us.’ Some other Old Latin MSS have ‘Judas Zelotes,’ and syr sin has ‘Judas son ( sic ) of James’ (syr cur is wanting here). Some inferior MSS and several Versions combine ‘LebbÃ¦us’ and ‘ThaddÃ¦us,’ as AV [Note: Authorized Version.] (‘L. whose surname was Th.’); but this is clearly a later explanation, and must be rejected. We see, then, that in Mt. ‘ThaddÃ¦us’ has the best attestation, and this alone is read in RV [Note: Revised Version.] , from which ‘LebbÃ¦us’ has completely disappeared. But how could ‘LebbÃ¦us’ have been invented? It has been suggested ( a ) that some early scribe, taking ‘ThaddÃ¦us’ and ‘LebbÃ¦us’ to be names of kindred meaning, the former from an Aramaic word denoting ‘breast,’ the latter from another denoting ‘heart,’ confused the two; or ( b ), with greater probability, that ‘LebbÃ¦us’ is a form of ‘Levi,’ introduced by some scribe who did not know that Levi and Matthew were the same person. It does not affect these explanations if, with Dalman, we hold that these derivations are in fact wrong, for the scribes were not necessarily qualified to be good philologers.
After NT times Thaddeus (Syr. Taddai ) was of ten confused with Addai, who was said to be one of the Seventy disciples, and who, being seat to Edessa, healed Abgarus (see Smith-Wace, Dict. Chr. Biog. iv. 875). In a list of Apostles given in Lagarde’s Appendix to the Apostolic Constitutions (p. 283), ThaddÃ¦us, ‘who is LebbÃ¦us and Judas,’ is distinguished from ‘Judas of James,’ and is said to have preached at Edessa, to have been buried in Egypt, and to have been crucified.
A. J. Maclean.
A Dictionary of Early Christian Biography 
Thaddaeus. Eusebius ( Hist. Eccl. i. 13) gives a story, which he says he found in the archives of Edessa, that after the ascension of our Lord, the apostle Judas Thomas sent Thaddaeus, one of the seventy disciples, to Edessa, to king Abgarus the Black, and that he cured the king of a serious illness, converted him with all his people to Christianity, and died at Edessa after many years of successful labours. The name of this apostle of the Edessenes is given by the Syrians as Addaeus ( Doctrina Addai, ed. Phillips, p. 5, Eng. trans. 1876), and it is possible that Eusebius misread the name as Thaddaeus. Thaddaeus was at a later date confused with the apostle Judas Thaddaeus. The documents given by Eusebius contain a correspondence between Abgar and our Lord, which of course is spurious. Cf. R. A. Lipsius, Die Edessenische Abgarsage kritisch untersucht (Braunschweig, 1880), and in D. C. B. vol. iv.; also, by the same, Die apokryphen Apostelgeschichten, vol. ii. 2, 178â€“201, and Suppl. p. 105; also Texeront, Les Origines de lâ€™Eglise dâ€™Edesse et la lÃ©gende dâ€™Abgar (Paris, 1888).
Bridgeway Bible Dictionary 
Little is known of Thaddaeus, apart from his appointment as one of Jesus’ twelve apostles. From the comparison of the lists of names in the four Gospels, it seems that ‘Thaddaeus’ was another name for Judas the son of James ( Matthew 10:3; Mark 3:18; Luke 6:16; John 14:22; Acts 1:13). (In some versions he is called the brother of James and given an alternative name, Lebbaeus.)
Fausset's Bible Dictionary 
Mark 3:18. Same as Lebbaeus or Judas not Iscariot ( John 14:22). (See Jude .) The Sinaiticus and Vaticanus manuscripts read in Matthew 10:3 only "Thaddaeus, "omitting "and Lebbaeus whose surname was."
Hawker's Poor Man's Concordance And Dictionary 
One of the Apostles of Christ, this was his surname, for Lebbeus was his former name. (See Matthew 10:3) If his name was derived from Jaduh or Thaduh, it signifies praise.
Easton's Bible Dictionary 
Mark 3:18 Matthew 10:3 Luke 6:16 John 14:22
Holman Bible Dictionary 
Morrish Bible Dictionary 
See JUDAS No 2.
International Standard Bible Encyclopedia 
tha - dē´us ( Θαδδαῖος , Thaddaı́os ): One of the Twelve Apostles ( Matthew 10:3; Mark 3:18 ). In Matthew 10:3 the King James Version, the reading is "Lebbaeus, whose surname was Thaddaeus." The name corresponds to Judas, the son (Revised Version), or brother (the King James Version), of James, given in the lists of Luke 6:16; Acts 1:13 . See Judas Not Iscariot; Lebbaeus .
The "Gospel of the Ebionites," or "Gospel of the Twelve Apostles," of the 2nd century and mentioned by Origen, narrates that Thaddaeus was also among those who received their call to follow Jesus at the Sea of Tiberias (compare Matthew 4:18-22 ). See also Simon The Cananaean .
According to the "Genealogies of the Twelve Apostles" (compare Budge, Contendings of the Apostles , II, 50), Thaddaeus was of the house of Joseph; according to the "Book of the Bee" he was of the tribe of Judah. There is abundant testimony in apocryphal literature of the missionary activity of a certain Thaddaeus in Syria, but doubt exists as to whether this was the apostle. Thus (1) according to the "Acts of Peter" (compare Budge, II, 466 ff) Peter appointed Thaddaeus over the island of Syria and Edessa. (2) The "Preaching of the blessed Judas, the brother of our Lord, who was surnamed Thaddaeus" (Budge, 357 ff), describes his mission in Syria and in Dacia, and indicates him as one of the Twelve. (3) The "Acta Thaddaei" (compare Tischendorf, Acta Apostolorum Apocrypha , 1851,261 ff) refers to this Thaddaeus in the text as one of the Twelve, but in the heading as one of the Seventy. (4) The Abgar legend, dealing with a supposed correspondence between Abgar, king of Syria, and Christ, states in its Syriac form, as translated by Eusebius ( Historia Ecclesiastica , I, xiii, 6-22) (compare Thomas ), that "after the ascension of Christ, Judas, who was also called Thomas, sent to Abgar the apostle Thaddaeus, one of the Seventy" (compare Hennecke, Neutestamentliche Apokryphen , 76 ff). Jerome, however, identifies this same Thaddaeus with Lebbaeus and "Judas ... of James" of Luke ( Luke 6:16 ). Hennecks (op. cit., 473, 474) surmises that in the original form of the Abgar legend Thomas was the central figure, but that through the influence of the later "Acts of Thomas", which required room to be made for Thomas' activity in India, a later Syriac recension was made, in which Thomas became merely the sender of Thaddaeus to Edessa, and that this was the form which Eusebius made use of in his translation According to Phillips (compare Phillips, The Doctrine of Addai the Apostle ), who quotes Zahn in support, the confusion may be due to the substitution of the Greek name Thaddaeus for the name Addai of the Syriac manuscripts. See Apocryphal Acts .
The general consensus seems to indicate, however, that both Thomas and Thaddaeus the apostle had some connection with Edessa. Of the various identifications of Thaddaeus with other Biblical personages which might be inferred from the foregoing, that with "Judas ... of James" is the only one that has received wide acceptance.
The burial place of Thaddaeus is variously placed at Beirut and in Egypt. A "Gospel of Thaddaeus" is mentioned in the Decree of Gelasius.
- ↑ Thaddaeus from Hastings' Dictionary of the Bible
- ↑ Thaddaeus from A Dictionary of Early Christian Biography
- ↑ Thaddaeus from Bridgeway Bible Dictionary
- ↑ Thaddaeus from Fausset's Bible Dictionary
- ↑ Thaddaeus from Hawker's Poor Man's Concordance And Dictionary
- ↑ Thaddaeus from Easton's Bible Dictionary
- ↑ Thaddaeus from Holman Bible Dictionary
- ↑ Thaddaeus from Morrish Bible Dictionary
- ↑ Thaddaeus from International Standard Bible Encyclopedia