Exodus 13:17

AND it was when Pharoh had released the people, that the Lord did not conduct them by the way of the land of the Phelishtaee though that was the near one; for the Lord said, Lest the people be affrighted in seeing their brethren who were killed in war, two hundred thousand men of strength of the tribe of Ephraim, who took shields, and lances, and weapons of war, and went down to Gath to carry off the flocks of the Phelishtaee; and because they transgressed against the statute of the Word of the Lord, and went forth from Mizraim thirty years before the (appointed) end of their servitude, they were delivered into the hand of the Phelishtaee, who slew them. These are the dry bones which the Word of the Lord restored to life by the ministry (hand) of Yechezekel the prophet, in the vale of Dura; but which, if they (now) saw them, they would be afraid, and return into Mizraim.

AND G-D LED THEM NOT BY THE WAY OF THE LAND OF THE PHILISTINES BECAUSE, as will be explained. Ramban will suggest further on in the text that the word ki should be understood here as “although.” The J.P.S. translation follows Ramban’s explanation. IT WAS NEAR. “It would therefore be easy [for the Israelites] to return to Egypt by the same route. There are many Midrashic explanations, [but the above is the plain sense of Scripture].” Thus the language of Rashi. This is also the opinion of Rabbi Abraham ibn Ezra, who explained the purport of the verse to be that G-d led them not by the way of the land of the Philistines “because” it was near. They might therefore be filled with regret [when they experience war], and they would immediately return to Egypt.
In my opinion, if their explanations were correct, the expression for G-d said would have been mentioned in first place in the verse, in which case the verse would read: “and G-d led them not by the way of the land of the Philistines, for G-d said, Because it is near, lest peradventure the people repent!”, etc. In other words, Ramban argues that according to Rashi and Ibn Ezra, the reason for G-d’s choice of the route by the wilderness and not by the land of the Philistines [because it was near], should have followed after the expression for G-d said. But the correct interpretation is that [the expression in question does not state the reason for G-d’s choice but merely] states that G-d led them not by the way of the land of the Philistines although it was near and it would have been advantageous to lead them by that route, for G-d said: Lest peradventure the people repent when they see war, and they return to Egypt.
The reason they would experience war if they went by the way of the land of the Philistines, is that the Philistines would surely not have given them permission to go peacefully through their land, and thus they might return to Egypt. But by the way of the wilderness, they would not see war until they came to the lands of Sihon and Og, the kings of the Amorites, which were given to them [i.e. to Israel]. At that time, they were already far from Egypt, [and there was thus no reason to fear that they would be tempted to return to Egypt because of war]. The war of Amalek in Rephidim was no reason for the Israelites to return to Egypt, since they did not pass through the land of the Amalekites. Rather, Amalek came from his country and warred against them because of his hatred of Israel. Even if they were to take their own course to return to Egypt, it would be to no avail since Amalek would fight them on the way. Besides, they were already far from Egypt because of the circuitous route which they had followed, and they knew of no other route.
Now Rashi commented: “When they see war. For instance, the war of the Canaanite and the Amalekite.. If they had proceeded by the direct route, they would have then turned back. For after He had made them go round by a circuitous way they said, Let us make a captain and go back to Egypt,, 14:4. and how much more so would they have said it had He led them by a straight road!”
The purport of that which Scripture states, and G-d led them not… But G-d led the people about, by the way of the wilderness, is that when they journeyed from Succoth, a pillar of cloud began to go before them. It did not go by the way of the land of the Philistines but instead went by the way of the wilderness of Etham, and the Israelites walked after it. The cloud then rested in Etham and they encamped there, and that was at the edge of the wilderness.

ויהי בשלח פרעה את העם, when G’d intended to bring them to the land of Canaan, but did not want to lead them through the land of the Philistines although it was the closest route,

כי קרוב הוא, and G’d feared that when faced with the need to conduct battles they would appoint an alternate leader in order to return to Egypt and submit to the Egyptians. We know that the Israelites tried to do this several times whenever they felt frustrated. (Examples are Numbers 14,3, Numbers 11,5) The disgruntled Israelites on such occasions “suddenly remembered” how good they had it in Egypt, citing the fish they ate for free, etc., as examples of their having been better off in Egypt. In light of what happened, although the Israelites did not have to face the armed might of the Philistines, G’d’s foresight in not leading them on that route seems extremely understandable. As a result of such considerations we find ויסב את העם דרך המדבר, that G’d made the Israelites take a much longer route in the direction of the Sea of Reeds. Moses described that had the Israelites traveled a straight path from their point of departure the whole journey would not have required more than 11 days. (Deuteronomy 1,2). Proof that the route to Egypt via the land of the Philistines is the shortest and most traveled route is furnished by Yitzchok’s declared intention to move to Egypt on account of the famine in the land of Canaan if G’d had not ordered him to stay in that land and he settled in the land of the Philistines while already on the way to Egypt (Genesis 26,3-6).

ויהי בשלח...ולא נחם אלוקים דרך ארץ פלשתים, even though it had been G’d’s plan to lead the Israelites to Mount Sinai to receive the Torah there, and only from there to the land of Israel, as He stated Himself in Exodus 6,7-8 :”I will take you as My people, and I will bring you to the land, etc.,” at this point, G’d’s plan was to lead them to the Sea of Reeds, which was neither the route to the land of the Philistines, nor the route that led to Mount Sinai. [we must remember that Moses had stood at Chorev=Mt Sinai at the burning bush and he did not have to cross the sea to do this. Ed.] The major reason for this was to bring about the drowning of Pharaoh and his army in the sea. [it is important to always remember that due to man’s free will, G’d cannot deal with man in the way He deals with inert objects or even animals, none of which could oppose Him. G’d needs to create a scenario which gives man a chance to delude himself, thus bringing him to act in a manner enabling G’d to insure that His design will be carried out. Ed.] An example of G’d acting in this manner is described in Judges 4,7 where G’d Himself speaks about how He “dragged” Sisera and his army and 900 armoured vehicles across the river Kishon to face Barak. The simplest route to get to the Sea of Reeds was by traversing the land of the Philistines. דרך ארץ פלשתים, G’d did not want them to travel this route

כי קרוב הוא because this route was too close to Egypt, afforded too easy a way to return to Egypt. Also, seeing it was a much traveled route, too many travelers would be able to report to Pharaoh about the Israelites and also too many Egyptians could keep the Israelites informed of what transpired in their country. If the Israelites would have to face combat

בראותם מלחמה, when they would hear that the Egyptians were mobilizing for war preparatory to chasing after the Israelites, the latter would no doubt return to Egypt out of fear of being killed. This is why G’d decided to lead them on a route not frequented by travelers at all.

כי קרוב, “because the people were close to the Lord,” as stated in Psalms 148.14: לבני ישראל, עם קרובו הללוי-ה, “for Israel, the people close to Him.” This is the reason why He led them not as in the custom of the world. An alternate interpretation of the line above: seeing that the land of the Philistines was so close to Egypt, as we know from Genesis 10,13-14:למצרים ילד את לודים...אשר יצאו משם פלשתים, “and Mitzrayim begat Ludim....from whom the Philistines are descended.”