Ellicott's Commentary On The Whole Bible
1 Samuel 28:1
The Philistines gathered their armies together for warfare. — This was evidently, as Jose-phus remarks, a great effort on the part of the Philistines. It was no ordinary raid or border incursion, such as seems to have been so frequent all through the reign of Saul. Since their defeat in the Valley of Elah, which followed the single combat between Goliath and David, no such Philistine army had been gathered together. We are struck at once with the presence of the enemy in the heart of the land, no longer choosing the well-known and often-contested “Marches,” or border districts. The Philistines are now strong enough to strike a blow at the centre of the kingdom, and to challenge a battle on the plain of Jezreel. or Esdraelon, north of Ephraim and Issachar. They probably marched along the sea-border of Canaan, collecting their forces as they advanced from each of their well-known military centres, and then, turning eastward, invaded the land by the Valley of Jezreel, or Esdraelon. They marched still eastward, and took up a strong position on the slopes of one of the groups of mountains that enclosed the broad plain of Jezreel toward the east, near the town of Shunem. King Saul, quickly assembling the fighting men of Israel, marched in pursuit, and coming up with them in the Esdraelon plain, took up his position opposite the Philistines — only a few miles parting the two hosts — on the slopes of another group of mountains, known as Mount Gilboa, lying to the south of the Philistine frontier. (There is a map of the Plain of Esdraelon in Stanley’s Jewish Church, vol. ii., Lecture 21, illustrative of this closing scene in Saul’s career, well worth consulting.)
And Achish said. — David soon found into what a grievous error he had fallen by taking refuge with the hereditary foes of his people. Want of faith and patience had urged him to take this unhappy step. The sixteen months he had spent in Phihstia had been certainly successful, inasmuch as they had strengthened his position as a “free lance” captain, but nothing more. They had been stained by bloodshed and cruelty. His life, too, was a life of duplicity and falsehood. The results of his unhappy course of action were soon manifest. His nation sustained a crushing and most humiliating defeat, which he narrowly escaped being obliged to witness, if not to contribute to. His own general recognition as king was put off for nearly seven years, during which period a civil war hindered the development of national prosperity; besides which, during this time of internal divisions the seeds were too surely laid of the future disastrous separation of Judah and the south from the northern tribes — a division which eventually took place in his grandson’s time, when his strong arm and Solomon’s wisdom and power were things of the past.
The summons of Achish to his great military vassal was perfectly natural: indeed, Achish had no reason to suspect that such a campaign as the one the Philistines were about to undertake against King Saul would be in any way distasteful to the wronged and insulted David. Not improbably the presence of David and his trained force — including, as the wily Philistine well knew, some of the bravest souls in Israel — encouraged Achish and the other Philistine lords to this great and, as it turned out, supreme effort against Israel. The King of Gath and his colleagues in Philistia saw that, in the divided state of Israel, their chances of success were very great, and it is highly probable that they looked forward to establishing their friend and follower David on the throne of Saul as a Philistine vassal king.