What does 2 Samuel 14:31 mean?

Joab, nephew of King David and commander of the army, has a very reasonable question for the king's son, Absalom, under restrictions for killing his brother: Why did your servants set my barley crops on fire? He uses no honorific or respectful language. Despite Absalom's pedigree, he's currently barred from the royal court, a mild punishment David ordered for murdering his brother (2 Samuel 14:24).

Absalom doesn't find the punishment mild. He's waited two years to be reintegrated into his family and political life. Joab brought him back to Jerusalem from exile, It's logical for Absalom to think Joab could pave the way to reconciliation with David. But Absalom sent two messages, and Joab ignored both. Absalom decided that setting Joab's field on fire would force his attention (2 Samuel 14:28–30) It's unclear how much of Joab's crop was burned or how extensive the fire was. It is enough to require Joab's response. Whether stated or not, there's a sense that Absalom may do worse if Joab doesn't meet with him.

That concern should make Joab cautious about Absalom's intentions. Absalom will go outrageous lengths to get what he wants. To avenge his sister and his own honor, Absalom murdered his brother (2 Samuel 13). Now, to initiate reconciliation with the king, he sets his benefactor's field on fire.

Once welcomed back into the royal court, his real manipulation can begin. Absalom gets a chariot with horses and fifty men to run in front of him while he drives through the city. He sits at the city gate where the elders decide legal cases. If someone from a far-off town comes to bring a case to the king, Absalom tells them David hasn't designated a court official to help them: but if he were king, there would be justice (2 Samuel 14:1–4)! Within four years, Absalom wins the hearts of the people enough to drive David into exile and take the throne (2 Samuel 15).