Judges - Chapter 15
Foxes and Donkeys
Samson had left his wife with her father. He later went to reclaim her, only to find that the father had given her away to another man. Since she was not divorced from Samson, this was blatant adultery, tacitly sanctioned by the local Philistine community in violation of the Seven Universal Laws. Samson tied foxes together by the tails with torches and let them loose through the Philistines' fields, burning down their crops. When the Philistines heard of this, they burned the adulterous woman and her father. Samson reprimanded them that that's what should have been done in the first place.
The men of the Tribe of Judah were concerned that Samson was stirring up trouble with the Philistines and that it would come back to bite them. He allowed them to arrest him and to turn him over to the Philistines, but when they handed him over, he broke his bonds, grabbed a donkey's jawbone and killed 1,000 of the enemy troops.
Even though Samson's story is not yet finished, the Navi records here that he judged for twenty years. The Radak (on verse 16:31 in the next chapter) notes that this is because this incident was the high point of Samson's career. His decline now begins.