Matthew 27:3

Repented himself (metamelhqei). Probably Judas saw Jesus led away to Pilate and thus knew that the condemnation had taken place. This verb (first aorist passive participle of metamelomai) really means to be sorry afterwards like the English word repent from the Latin repoenitet, to have pain again or afterwards. See the same verb metamelhqei in Matthew 21:30 of the boy who became sorry and changed to obedience. The word does not have an evil sense in itself. Paul uses it of his sorrow for his sharp letter to the Corinthians, a sorrow that ceased when good came of the letter ( 2 Corinthians 7:8 ). But mere sorrow avails nothing unless it leads to change of mind and life (metanoia), the sorrow according to God ( 2 Corinthians 7:9 ). This sorrow Peter had when he wept bitterly. It led Peter back to Christ. But Judas had only remorse that led to suicide.