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 Chronicles 10:1
ch1 10:1SAUL'S OVERTHROW AND DEATH. (Ch1 10:1-7)
Now the Philistines fought against Israel--The details of this chapter have no relation to the preceding genealogies and seem to be inserted solely to introduce the narrative of David's elevation to the throne of the whole kingdom. The parallel between the books of Samuel and Chronicles commences with this chapter, which relates the issue of the fatal battle of Gilboa almost in the very same words as Sa1 31:1-13.
1 Chronicles 10:3
ch1 10:3the battle went sore against Saul; and the archers hit him, and he was wounded--The Hebrew words may be thus rendered: "The archers found (attacked) him, and he feared the archers." He was not wounded, at least not dangerously, when he resolved on committing suicide. The deed was the effect of sudden terror and overwhelming depression of spirits [CALMET].
1 Chronicles 10:4
ch1 10:4his armour-bearer would not; for he was sore afraid--He was, of course, placed in the same perilous condition as Saul. But it is probable that the feelings that restrained him from complying with Saul's wish were a profound respect for royalty, mingled with apprehension of the shock which such a catastrophe would give to the national feelings and interests.
1 Chronicles 10:6
ch1 10:6Saul died, and his three sons, and all his house--his sons and courtiers who were there engaged in the battle. But it appears that Ish-bosheth and Mephibosheth were kept at Gibeah on account of their youth.
1 Chronicles 10:10
ch1 10:10THE PHILISTINES TRIUMPH OVER HIM. (Ch1 10:8-14)
put his armour in the house of their gods--It was common among the heathen to vow to a national or favorite deity, that, in the event of a victory, the armor of the enemy's king, or of some eminent leader, should be dedicated to him as an offering of gratitude. Such trophies were usually suspended on the pillars of the temple.
fastened his head in the temple of Dagon--while the trunk or headless corpse was affixed to the wall of Beth-shan (Sa1 31:10).
1 Chronicles 10:13
ch1 10:13Saul died for his transgression which he committed against the Lord--in having spared the king of the Amalekites and taken the flocks of the people as spoils [Sa1 15:9], as well as in having consulted a pythoness [Sa1 28:7]. Both of these acts were great sins--the first as a violation of God's express and positive command [Sa1 15:3], and the second as contrary to a well-known statute of the kingdom (Lev 19:31).
1 Chronicles 10:14
ch1 10:14And inquired not of the Lord--He had done so in form (Sa1 28:6), but not in the spirit of a humble penitent, nor with the believing confidence of a sincere worshipper. His enquiry was, in fact, a mere mockery, and his total want of all right religious impressions was manifested by his rushing from God to a wretched impostor in the service of the devil [Sa1 28:7].