Identity
Judas Iscariot is consistently listed last among the Twelve in every apostolic list, always identified as "the one who betrayed him" (Matthew 10:4; Mark 3:19; Luke 6:16). "Iscariot" most likely derives from ish Kerioth, "man of Kerioth," a town in Judea — which would make Judas the only one of the Twelve from Judea in the south, the rest being Galileans, a detail some interpreters find suggestive (an outsider among the group geographically) without it being possible to draw firm conclusions from it. He served as treasurer for the group (John 12:6, 13:29), and John's Gospel bluntly editorializes that he "used to help himself" to the money kept in the common purse — the only apostle the Gospels describe in explicitly dishonest terms even before the betrayal itself.
The betrayal
All four Gospels record that Judas arranged with the chief priests to hand Jesus over, receiving thirty pieces of silver (Matthew 26:14–16) — an amount Matthew explicitly ties to Zechariah 11:12–13's prophecy about a shepherd's wages "thrown to the potter." John's Gospel frames the act starkly in spiritual terms: "Satan entered into him" (John 13:27) after Jesus identified him at the Last Supper by handing him a piece of bread — while also preserving the deep discomfort of the disciples, none of whom, when Jesus announced someone would betray him, immediately suspected Judas (each instead asked "Surely not I, Lord?"). Judas identified Jesus to the arresting soldiers in Gethsemane with a kiss — an act of intimate greeting turned into the signal for arrest, which is why "a Judas kiss" remains an idiom for betrayal by someone trusted.
Remorse and death
Matthew's Gospel alone records what happened next: overcome with remorse once he saw Jesus condemned, Judas returned the silver to the chief priests, declaring "I have sinned by betraying innocent blood," before going out and hanging himself (Matthew 27:3–5). Acts 1:18–19 gives a difficult-to-fully-reconcile second account — that Judas "fell headlong" in a field purchased with the betrayal money, his body bursting open — which most harmonizing readings take as a fall following (or as part of) the same death, perhaps the rope or branch giving way, though the two accounts' differing emphasis (Matthew stresses Judas's active remorse and suicide; Acts stresses a grim, almost judicial end) is honestly noted by careful readers rather than smoothed over. The place was remembered as Akeldama, "Field of Blood" (Acts 1:19; Matthew 27:8). Peter's speech in Acts 1 treats Judas's betrayal as, in a difficult but real sense, foreseen in Scripture (citing Psalms 69 and 109) while not thereby erasing Judas's own culpability — the same tension between divine foreknowledge and genuine human responsibility that runs through the whole crucifixion narrative. Matthias was chosen by lot to restore the number of the Twelve (Acts 1:23–26).
Theological weight, honestly held
Judas occupies a uniquely difficult place in Christian reflection: Jesus states plainly that "it would have been better for that man if he had not been born" (Matthew 26:24), language of real and severe judgment, while the same Gospels are equally clear that the crucifixion Judas set in motion is the very event that accomplishes salvation — meaning Judas's act is simultaneously genuinely evil and, in the mystery of providence, woven into God's redemptive purpose without that purpose excusing the evil of the act itself. Different Christian traditions have handled this tension differently (some later apocryphal and Gnostic texts, notably the so-called Gospel of Judas, attempted to rehabilitate him as a secretly enlightened, obedient figure — a reading virtually no mainstream tradition, ancient or modern, has accepted), but the canonical Gospels themselves never soften the act into something other than betrayal, even while treating Judas as a real, once-called disciple rather than a symbol invented purely for narrative convenience.
Why it matters
Judas's story resists easy resolution, and that's arguably the honest, faithful way to hold it rather than a gap to be explained away: a man who walked with Jesus for years, was trusted enough to hold the money, and still chose betrayal — a sober reminder that proximity to Christ, even years of it, guarantees nothing about the state of a person's heart, and a hard mirror for any church culture where visible religious participation can pass for genuine discipleship.