The Parsha begins with the words, “It happened when Pharaoh sent out the people that G-d did not lead them by way of the land of the Philistines, though it was near, for G-d said, ‘perhaps the people will reconsider when they see a war, and they will return to Egypt’.” After escaping from Egypt, the direct route to the heart of the Land of Israel would have been along the Mediterranean coast which would lead them directly into Philistine territory after a relatively short journey. Abarbanel, and other commentaries as well, explain that the Torah is telling us that having had no experience with warfare and assuming that no nation would allow such a multitude to pass peacefully through its territory, the people would prefer to return to Egyptian enslavement rather than risk death at the hands of Philistine warriors. Also, the Midrash tells us that previously some members of the tribe of Ephraim had managed to leave Egypt prematurely and were soundly defeated by the Philistines. The people would encounter the bones of their slaughtered brethren and would be frightened into returning to Egypt. By taking them on a much longer, circuitous route, G-d would give them time to overcome and avoid that fear.
Another possible explanation is that since the Torah is emphasizing that “Pharaoh sent out the people” we have to keep in mind that Pharaoh had sent them out only to celebrate a festival to G-d that would require a three-day excursion into the desert. If G-d led them directly on the short route toward Philistine territory, Pharaoh would realize that Moshe had lied to him and was seeking to escape permanently. Initially, then, G-d led them in a way which appeared to be consistent with Pharaoh’s intentions.
However, Abarbanel states that the most logical explanation for not going directly to the Land of Israel was to provide the opportunity for the splitting of the sea and the drowning of Pharaoh and the Egyptian army. The news of this final, overwhelmingly miraculous deliverance would spread throughout the region, instilling the fear of G-d in every nation and emboldening Bnei Yisrael to confront the powerful inhabitants of the Promised Land. After leaving Egypt, G-d gives Moshe specific instructions to turn back and encamp in such a way that they would give the appearance of not knowing where they were going. When Moshe had consistently asked permission to lead a three-day excursion, Pharaoh had assumed that Moshe had a specific place in mind and would go there directly. Now that they had turned back as a result of apparent confusion, Pharaoh suspected that Moshe had deceived him all along and as a result decided to pursue them. Even though G-d says, “I shall strengthen the heart of Pharaoh and he will pursue them”, Abarbanel makes it clear that G-d is not depriving Pharaoh of his free will. Rather, He is manipulating specific circumstances so that Pharaoh will feel compelled on his own to change his mind and pursue.
Abarbanel’s approach to the phrase “I will strengthen his heart”, which appears several times in the narrative of the Exodus, is consistent. He bases his approach on the verse in Proverbs (21:1) “Like streams of water, so the hearts of kings are in G-d’s hands.” G-d doesn’t simply put ideas in their hearts and words in their mouths against their will. Rather, just like farmers direct rainfall into reservoirs, canals and irrigation ditches, G-d directs events in such a way that kings and rulers are compelled to take the kinds of actions that will make a lasting imprint on history.