What does 2 Samuel 15:15 mean?

Absalom, David's son, has won the affections of the people of Israel (2 Samuel 15:6). He's declared himself king in Hebron, and he and a large crowd are marching to Jerusalem. Some in his group helped plan this coup; some are human shields tricked into coming with him to Hebron. David can't tell which is which. His priority is to protect his household and his people. A civil war inside Jerusalem would be devastating. David's closest servants immediately declare their devotion to him and not to Absalom. He gathers those he knows are loyal and flees (2 Samuel 15:7–12).

Throughout the day, David gets a better idea of who is still with him and who has joined Absalom. His Philistine bodyguards and mercenaries will do whatever he asks (2 Samuel 15:18–21). The priests and their sons are ready to follow David with the ark, but David realizes they'd be more effective as spies in Absalom's court (2 Samuel 15:24–29). David loses his counselor Ahithophel but is more than compensated by his old friend Hushai (2 Samuel 15:31–32). Despite losing much of the army, Joab (2 Samuel 8:16) and his brother Abishai remain true (2 Samuel 18:2).

This is enough. Hushai's influence, the priest's warnings, and Joab's military experience make very quick work of Absalom's rebellion. Within a short time, Absalom will be dead (2 Samuel 18:16–15). When the rebellious people realize what's happened, they fall over themselves trying to reinstate David as king (2 Samuel 19:8–10).