King Saul's hasty retreat from the Philistine army began when Prince Jonathan, with a battalion of 1,000 men, attacks and destroys a Philistine camp in a small town near what is now Jerusalem. His father , King Saul, backs him up by leading 2,000 men into the area to patrol the towns and communities.
Philistines retaliate with overwhelming force: 3,000 chariots pulled by 6,000 horses. And there are more infantry than anyone can count.
"When Israel saw they were in trouble, most of the army retreated to anything they could crawl into or behind: caves, rocks, tombs, dry wells called cisterns, and dirt holes in the ground. They got invisible fast.Some jumped the Jordan. They crossed the Jordan River into territory of Gad’s tribe and the land of Gilead. But Saul stayed at Gilgal, with a lot of terrified Israelite citizens" (1 Samuel 13:6-7).Saul waited to attack for seven days, to give time for Samuel to get there. Samuel told him to do that. But Saul’s fighters were quickly slipping out of camp and running away.
Meanwhile, Philistines set up camp in the hills around Michmash, in the area where the Israelite had been before they ran away.
One more thing: "On the day of the battle, Saul and his son Jonathan each had a sword and spear. No one else did. There weren’t any weapons in town.A company of Philistines advanced to set up camp at the valley pass of Michmash."Israel didn’t have any ironsmiths who could make iron weapons or tools. Philistines outlawed it. They said, “Hebrews aren’t allowed to make swords or spears for themselves.”So, Israelites couldn’t sharpen or repair their iron plow tips, picks, axes, and sickles. They had to go to Philistine ironsmiths for that.
A bronze sword doesn't hold up well against an iron one.