Matthew Henry Commentary 1 Samuel 13:1-7

"Saul was [forty] years old when he began to reign; and when he had reigned two years over Israel, Saul chose him three thousand men of Israel, whereof two thousand were with Saul in Michmash and in the mount of Beth-el, and a thousand were with Jonathan in Gibeah of Benjamin: and the rest of the people he sent every man to his tent. And Jonathan smote the garrison of the Philistines that was in Geba: and the Philistines heard of it. And Saul blew the trumpet throughout all the land, saying, Let the Hebrews hear. And all Israel heard say that Saul had smitten the garrison of the Philistines, and also that Israel was had in abomination with the Philistines. And the people were gathered together after Saul to Gilgal. And the Philistines assembled themselves together to fight with Israel, thirty thousand chariots, and six thousand horsemen, and people as the sand which is on the sea-shore in multitude: and they came up, and encamped in Michmash, eastward of Beth-aven. When the men of Israel saw that they were in a strait (for the people were distressed), then the people did hide themselves in caves, and in thickets, and in rocks, and in coverts, and in pits. Now some of the Hebrews had gone over the Jordan to the land of Gad and Gilead; but as for Saul, he was yet in Gilgal, and all the people followed him trembling." — 1 Samuel 13:1-7 (ASV)

Saul reigned one year, and nothing particular happened; but in his second year, the events recorded in this chapter took place. For more than a year, he gave the Philistines time to prepare for war, and to weaken and to disarm the Israelites.

When people are puffed up by self-sufficiency, they are often led into folly. The chief advantages of the enemies of the church are derived from the misconduct of its professed friends. When Saul finally sounded an alarm, the people, dissatisfied with his management, or terrified by the power of the enemy, did not come to him or quickly deserted him.