A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Kings (1 Samuel) 28:1
sa1 28:1ACHISH'S CONFIDENCE IN DAVID. (Sa1 28:1-6)
The Philistines gathered their armies together for warfare, to fight with Israel--The death of Samuel, the general dissatisfaction with Saul, and the absence of David, instigated the cupidity of those restless enemies of Israel.
Achish said to David, Know thou assuredly, that thou shalt go out with me to battle--This was evidently to try him. Achish, however, seems to have thought he had gained the confidence of David and had a claim on his services.
1 Kings (1 Samuel) 28:2
sa1 28:2Surely thou shalt know what thy servant can do--This answer, while it seemed to express an apparent cheerfulness in agreeing to the proposal, contained a studied ambiguity--a wary and politic generality.
Therefore will I make thee keeper of mine head for ever--or, "my life"; that is, "captain of my bodyguard," an office of great trust and high honor.
1 Kings (1 Samuel) 28:3
sa1 28:3Now Samuel is dead, &c.--This event is here alluded to as affording an explanation of the secret and improper methods by which Saul sought information and direction in the present crisis of his affairs. Overwhelmed in perplexity and fear, he yet found the common and legitimate channels of communication with Heaven shut against him. And so, under the impulse of that dark, distempered, superstitious spirit which had overmastered him, he resolved, in desperation, to seek the aid of one of those fortune telling impostors whom, in accordance with the divine command (Lev 19:31; Lev 20:6, Lev 20:27; Deu 18:11), he had set himself formerly to exterminate from his kingdom.
1 Kings (1 Samuel) 28:4
sa1 28:4the Philistines . . . pitched in Shunem--Having collected their forces for a last grand effort, they marched up from the seacoast and encamped in the "valley of Jezreel." The spot on which their encampment was fixed was Shunem (Jos 19:18), now Sulem, a village which still exists on the slope of a range called "Little Hermon." On the opposite side, on the rise of Mount Gilboa, hard by "the spring of Jezreel," was Saul's army--the Israelites, according to their wont, keeping to the heights, while their enemies clung to the plain.
1 Kings (1 Samuel) 28:7
sa1 28:7SAUL SEEKS A WITCH, WHO, BEING ENCOURAGED BY HIM, RAISES UP SAMUEL. (1Sa. 28:7-25)
Then said Saul unto his servants, Seek me a woman that hath a familiar spirit--From the energetic measures which he himself had taken for extirpating the dealers in magical arts (the profession having been declared a capital offense), his most attached courtiers might have had reason to doubt the possibility of gratifying their master's wish. Anxious inquiries, however, led to the discovery of a woman living very secluded in the neighborhood, who had the credit of possessing the forbidden powers. To her house he repaired by night in disguise, accompanied by two faithful servants.
En-dor--"the fountain of the circle" (that figure being constantly affected by magicians) was situated directly on the other side of the Gilboa range, opposite Tabor; so that, in this midnight adventure, Saul had to pass over the shoulder of the ridge on which the Philistines were encamped.
1 Kings (1 Samuel) 28:8
sa1 28:8bring me him up, whom I shall name unto thee--This pythoness united to the arts of divination a claim to be a necromancer (Deu 18:11); and it was her supposed power in calling back the dead of which Saul was desirous to avail himself. Though she at first refused to listen to his request, she accepted his pledge that no risk would be incurred by her compliance. It is probable that his extraordinary stature, the deference paid him by his attendants, the easy distance of his camp from En-dor, and the proposal to call up the great prophet and first magistrate in Israel (a proposal which no private individual would venture to make), had awakened her suspicions as to the true character and rank of her visitor. The story has led to much discussion whether there was a real appearance of Samuel or not. On the one hand, the woman's profession, which was forbidden by the divine law, the refusal of God to answer Saul by any divinely constituted means, the well-known age, figure, and dress of Samuel, which she could easily represent herself, or by an accomplice--his apparition being evidently at some distance, being muffled, and not actually seen by Saul, whose attitude of prostrate homage, moreover, must have prevented him distinguishing the person though he had been near, and the voice seemingly issuing out of the ground, and coming along to Saul--and the vagueness of the information, imparted much which might have been reached by natural conjecture as to the probable result of the approaching conflict--the woman's representation--all of this has led many to think that this was a mere deception. On the other hand, many eminent writers (considering that the apparition came before her arts were put in practice; that she herself was surprised and alarmed; that the prediction of Saul's own death and the defeat of his forces was confidently made), are of opinion that Samuel really appeared.
1 Kings (1 Samuel) 28:24
sa1 28:24the woman had a fat calf . . . and she hasted, and killed it, &c.--(See on Gen 18:1-8).
1 Kings (1 Samuel) 28:25
sa1 28:25Then they rose up, and went away that night--Exhausted by long abstinence, overwhelmed with mental distress, and now driven to despair, the cold sweat broke on his anxious brow, and he sank helpless on the ground. But the kind attentions of the woman and his servants having revived him, he returned to the camp to await his doom.