Two Questions About The Beginning of Parshat B'Shalach

Why did God take Bnei Yisrael out of Egypt through the Sinai instead of directly through the land of the Plishtim?

God led Bnei Yisrael through the wilderness of Sinai as a way to test their faith and to prepare them to receive the Torah at Mount Sinai. The Gemara in Massechet Sotah (11b) states that God led Bnei Yisrael through the wilderness to test their faith and to teach them to rely on him.

The Midrash Tanchuma states that God led Bnei Yisrael through the wilderness so that they would be purified and ready to receive the Torah at Mount Sinai. The midrash explains that the journey was also a way for the people to escape the corrupting influences of Egypt and to demonstrate their devotion to God. Additionally, the midrash states that the journey was a way for God to show Bnei Yisrael his power and to demonstrate his love for them.

In Massechet Shabbat (87a), the Gemara describes the journey through the wilderness as a time of spiritual refinement and preparation for Bnei Yisrael to receive the Torah at Mount Sinai.

Why did Paroh change his mind and chase after Bnei Yisrael after he sent them from Egypt?

Rashi explains that Paroh changed his mind and pursued Bnei Yisrael because he feared that they would not return and he would lose his labor force. Rashi also states that Paroh was motivated by his pride and desire to maintain control over Bnei Yisrael.

The Ramban explains that Paroh changed his mind because he realized that Bnei Yisrael were not just leaving, but were going to worship God and that this would have negative consequences for his kingdom. Ramban states that Paroh was motivated by his fear that the worship of the God of Israel would spread and undermine the power of the Egyptian gods.

Both Rashi and Ramban emphasize that Pharaoh's change of heart was motivated by a combination of fear, pride, and a desire to maintain control over both Bnei Yisrael and his kingdom.