Judas Iscariot the son of Simon. — The best MSS. read, Judas, the son of Simon Iscariotes. On the name see the list of the Apostles in Matthew 10:4. If we accept the most probable interpretation of Iscariot as Ish K’rîoth, a man of K’rîoth, — and this is supported by the variation of MSS. in this place, some of which read “from Kariotes,” and the best of which, as we see, apply the title Iscariot to Simon — then Judas belonged to the tribe of Judah (Joshua 15:25), and is the only one of the Apostles who was not a Galilean (Acts 2:7). This connects itself with the antagonistic position of the Jews from Jerusalem.
That should betray him. — Not indicating that Judas was then planning the betrayal. (Comp. John 13:2.) This remark is made by the writer to explain the strong words of the previous verse.
Being one of the twelve. — Or, although he was one of the Twelve, the exact shade of meaning of the participle being defined by the context. It marks, again, the tragic contrast between what might have been expected and what was actually realised. One of the Twelve, devil! one of the Twelve, the betrayer!