The passage of Michmash - The steep and precipitous path from Michmash to Geba, over the valley of Suweinit. The same term is used in Isaiah 10:28-29, where the march of the Assyrian army is described.

And the garrison of the Philistines went out to the passage of Michmash. According to Jarchi, these two places, Michmash where the Philistines were, and Gibeah where Saul and Jonathan were, lay on two hills over against each other, and there was a valley between them; and the garrison of the Philistines drew nigh to the passage of Michmash, which led to the side of Gibeah, to the valley between them, either with an intention to besiege Gibeah, or to dare Israel to come out and fight them: but rather it seems to be some strong pass between the rocks near Michmash, where the garrison placed themselves to guard and keep against any sudden surprise; see 1 Samuel 14:4. The Targum is,"the governor of the Philistines went out to the ford or passage of Michmash;''and Kimchi interprets it of the princes or generals of the army; these might go to mark out a camp, and pitch upon a proper place to draw up in a line of battle.

1 Samuel 13:23 forms the transition to the heroic act of Jonathan described in 1 Samuel 14.: "An outpost of the Philistines went out to the pass of Michmash;" i.e., the Philistines pushed forward a company of soldiers to the pass (מעבר, the crossing place) of Michmash, to prevent an attack being made by the Israelites upon their camp. Between Geba and Michmash there runs the great deep Wady es Suweinit, which goes down from Beitin and Bireh (Bethel and Beeroth) to the valley of the Jordan, and intersects the ridge upon which the two places are situated, so that the sides of the wady form very precipitous walls. When Robinson was travelling from Jeba to Mukhmas he had to go down a very steep and rugged path into this deep wady (Pal. ii. p. 116). "The way," he says in his Biblical Researches, p. 289, "was so steep, and the rocky steps so high, that we were compelled to dismount; while the baggage mules got along with great difficulty. Here, where we crossed, several short side wadys came in from the south-west and north-west. The ridges between these terminate in elevating points projecting into the great wady; and the most easterly of these bluffs on each side were probably the outposts of the two garrisons of Israel and the Philistines. The road passes around the eastern side of the southern hill, the post of Israel, and then strikes up over the western part of the northern one, the post of the Philistines, and the scene of Jonathan's adventure."

And the garrison of the Philistines went out to the passage of Michmash.

garrison: or, standing camp

13:15-23 See how politic the Philistines were when they had power; they not only prevented the people of Israel from making weapons of war, but obliged them to depend upon their enemies, even for instruments of husbandry. How impolitic Saul was, who did not, in the beginning of his reign, set himself to redress this. Want of true sense always accompanies want of grace. Sins which appear to us very little, have dangerous consequences. Miserable is a guilty, defenceless nation; much more those who are destitute of the whole armour of God.