2 Samuel 21:15

Moreover the Philistines had yet war again with Israel— It appears from chap. 2 Samuel 15:18 that Ittai, an exile from Gath, arrived at Jerusalem with all his men on the very eve of David's flight before his son Absalom; whence it is probable, that the Philistines, hearing of Absalom's rebellion, took that opportunity to shake off the Israelite yoke; and to that purpose drove out all the friends and favourers of David's government over them; and among the rest Ittai and his followers, who arrived very providentially at Jerusalem, to support David in the extremity of his distress. And as this revolt of the Philistines was succeeded by a long famine in David's dominions, we could not reasonably expect to hear of any measures taken by the king to chastise that revolt, till after the ceasing of this calamity; and then we immediately hear of the wars now recounted.