Contradiction with John 6:70-71
These verses state that Jesus knowingly chose Judas Iscariot despite knowing he would betray Him, whereas Mark 3:19 mentions the act of betrayal associated with Judas.
John 6:70-71: Jesus answered them, Have not I chosen you twelve, and one of you is a devil?
Contradiction with Luke 6:16
This verse identifies Judas Iscariot as the traitor from the outset, which seems to contradict Mark 3:19 by implying foreknowledge of his betrayal.
Luke 6:16: And Judas [the brother] of James, and Judas Iscariot, which also was the traitor.
Contradiction with Matthew 27:3-5
These verses describe a sense of remorse and regret in Judas after the betrayal, whereas Mark 3:19 simply lists him among the apostles without such context.
Matthew 27:3-5: Then Judas, which had betrayed him, when he saw that he was condemned, repented himself, and brought again the thirty pieces of silver to the chief priests and elders,
Contradiction with Acts 1:18-20
These verses mention the fate of Judas following his betrayal, which contrasts with the simpler calling of him by Jesus in Mark 3:19.
Acts 1:18-20: Now 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.