Luke 6:16

And Judas the brother of James
Of that James, that was the son of Alphaeus; though the Syriac and Arabic versions call him "the son of James", very wrongly: this Judas was also called Thaddaeus and Lebbaeus, and is the writer of the epistle that bears his name:

and Judas Iscariot, which also was the traitor;
both his surname and his character are mentioned, to distinguish him from the other Judas: it is easy to observe, that these twelve are mentioned by pairs, or couples, and so they were sent out, two by two; see ( Mark 6:7 ) as were also the seventy disciples afterwards; see ( Luke 10:1 ) There seems to be an allusion to the pairs and couples of the Jewish fathers and doctors, who in their succession are thus paired: Jose ben Joezer, and Joseph ben Jochauan; Joshua ben Perachia, and Nathan the Arbelite; Simeon ben Shetach, and Judah ben Tabai; Shemain and Abtalion; the two sons of Bethira, whose names were Judah and Joshua; Hillell and Shammai {s}: all before Christ's time.