The only one of the Apostles set off by himself in the lists is Judas Iscariot, who is traditionally remembered as the betrayer (Matthew 10:4; Mark 3:19; Luke 6:16) who sold his Master for thirty pieces of silver (Matthew 26:15). Iscariot is said to refer to his birthplace, Iscariot being a Hebrew phrase “man from [the town of] Kerioth or Carioth.”Judas is the Greek form of the Hebrew Judah.

John's Gospel in Chapter 6 describes a point at which many of Jesus' disciples abandoned him. “Will you also go away?” Jesus asked the Twelve. To which Simon Peter answered, “Lord, to whom shall we go? You have the words of eternal life and we believe, and are certain, that you are the Christ, the Son of the living God.” In reply, Jesus, speaking of Judas Iscariot, said, “Have I not chosen you twelve, one of whom is a devil?”

Matthew's account says that Judas, after realizing how wrong he had been in setting up his Master for crucifixion through betraying him into the hands of the Temple leaders, first threw away the pieces of silver he'd been paid in the Temple, then hanged himself in despair. The Temple leaders used the silver to buy a potter's field to “bury strangers in” (Matthew 27:3–7).

But Peter, in a sermon quoted by Luke in Acts 1:18, says that “this man purchased a field with the reward of iniquity and, falling headlong, he burst asunder in the midst, and all his bowels gushed out.” Catholic writer W. H. Kent suggests that by returning the pieces of silver to the Temple leaders, Judas “indirectly” paid for the field that Matthew says the Temple leaders bought for use as the potter's field.