New Defender's Study Bible Notes
6:70 is a devil. Judas was not a true disciple, but he did not “go away” (note John 6:66) at this time. He continued with the twelve until he could find opportunity to betray Jesus. Even at this time, however, he was a “devil.” The Greek word here is diabolos, and usually refers to the Devil. It seems most probable that Satan was already controlling Judas, though he didn’t “enter into” him and fully possess him until later (Luke 22:3).