Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
He was sore wounded - Better, "he was sore afraid" (compare Deu 2:25). Saul's fear is explained in Sa1 31:4.
All his men - This and similar expressions must not be taken too literally (compare Ch1 10:6). We know that Abner, and Ish-bosheth, and manymore survived the day of Gilboa.
The men on the other side of the valley - This must mean to the north of the plain of Jezreel, and would comprise the tribe of Naphtali, and Zabulon, and probably Issachar. But the text of Ch1 10:7 has "that were in the valley," limiting the statement to the inhabitants of the plain of Jezreel.
On the other side Jordan - This phrase most commonly means on the east of Jordan, the speaker being supposed to be on the west side. But it is also used of the west of Jordan, as here, if the text be sound.
The Philistines ... dwelt in them - One of the principal cities, Beth-shan, fell into their power at once Sa1 31:10.
In the house of Ashtaroth - This was doubtless the famous temple of Venus in Askelon mentioned by Herodotus as the most ancient of all her temples. Hence, the special mention of Askelon Sa2 1:20. The placing Saul's armour as a trophy in the temple of Ashtaroth was a counterpart to the placing Goliath's sword in the tabernacle Sa1 21:9. In Ch1 10:10 it is added that they "fastened Saul's head in the temple of Dagon," probably either in Gaza Jdg 16:21, or in Ashdod Sa1 5:1-3. This was, perhaps, in retaliation for the similar treatment of Goliath's head Sa1 17:54. The variations seem to imply that both this narrative and that in Ch1 10:1-14 are compiled from a common and a fuller document.
When the inhabitants of Jabesh-Gilead heard ... - See Sa1 11:1-15. This is a touching and rare example of national gratitude.
burnt them - Burning was not the usual mode of sepulture among the Hebrews. But in this case from a pious desire to disguise the mutilation of the headless corpses, and exempt them from any possible future insult, the men of Jabesh burned the bodies, yet so as to preserve the bones Sa1 31:13; Sa2 21:12.
Under a tree - Rather, "Under the tamarisk," a well-known tree at Jabesh which was standing when this narrative was written.
They fasted seven days - In imitation of the mourning for Jacob (marginal reference). They would give full honor to Saul though he was fallen.