A.T. Robertson Commentary John 6:71

"Now he spake of Judas [the son] of Simon Iscariot, for he it was that should betray him, [being] one of the twelve." — John 6:71 (ASV)

Of Simon Iscariot (Σιμωνος Ισκαριωτου). So his father was named Iscariot also, a man of Kerioth (possibly in Judah, Joshua 15:25, possibly in Moab, Jeremiah 48:24), not in Galilee. Judas was the only one of the twelve not a Galilean. The rest of the verse is like 12:4.

One of the twelve (εις εκ των δωδεκα). The eternal horror of the thing.