2 Samuel 18:15

And ten young men that bare Joab’s armour compassed about and smote Absalom, and slew him.

Cross-reference

2 Samuel 12:10 Prophetic fulfillment

In 2 Samuel 12:10, Nathan prophesied the sword would never leave David's house—Absalom's death here fulfills that judgment on David's family.

Proverbs 17:11 says an evil rebel will face a cruel messenger—Joab's armor-bearers became that messenger, executing judgment on Absalom.