I read in 2 Corinthians, chapter 7 today, this: For godly sorrow worketh repentance to salvation not to be repented of: but the sorrow of the world worketh death.
My bible has little cross reference verses and the “sorrow of the world worketh death” has this verse: Matthew 27:4,5,( I included verse 3) which says:  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,
 Saying, I have sinned in that I have betrayed the innocent blood. And they said, What is that to us? see thou to that.
 And he cast down the pieces of silver in the temple, and departed, and went and hanged himself.
And, the verse about GODLY sorrow worketh repentance to salvation not to be repented of was this: Jeremiah 31:18-20: I have surely heard Ephraim bemoaning himself thus; Thou hast chastised me, and I was chastised, as a bullock unaccustomed to the yoke: turn thou me, and I shall be turned; for thou art the LORD my God.
 Surely after that I was turned, I repented; and after that I was instructed, I smote upon my thigh: I was ashamed, yea, even confounded, because I did bear the reproach of my youth.
 Is Ephraim my dear son? is he a pleasant child? for since I spake against him, I do earnestly remember him still: therefore my bowels are troubled for him; I will surely have mercy upon him, saith the LORD.
Isn’t that so neat? Very well explained! I wish I had the entire bible memorized, so I could do that kind of cross-referencing!