A similar ideas is found here in this dvar Torah by Rabbi Moshe Kormornick of www.shortvort.com, a great Torah website with thousands of short vorts for every occasion - from Bris and sheva brachos to the Parsha! This is an article that Rabbi Kormornick emailed out in his weekly shortvort email. It's free to sign up at www.shortvort.com and highly recommended! See also - http://www.shortvort.com/parasha/shemos/bo and http://www.shortvort.com/parasha/shemos/beshalach
Hope this is useful... (the footnotes did not copy over but they are at the bottom!)
וַיֻּגַּד לְמֶלֶךְ מִצְרַיִם כִּי בָרַח הָעָם
And it was told to the king of Egypt that the People had fled… (14:5)
Moshe had asked Pharaoh to grant the Jewish People three days leave from Egypt to go into the wilderness to serve Hashem , and before they left, Moshe told everyone to borrow expensive vessels and clothes from the Egyptians . When, after three days the Jewish People were not returning, Pharaoh’s heart was hardened and he set chase against them.
How could Moshe tell the Jewish people to borrow expensive vessels and clothes from the Egyptians before they left Egypt, and how could he ask Pharaoh for permission to take the whole Jewish People into the desert for three days in order to go and serve Hashem, surely they were never planning on returning?
Rav Shmuel Weinbaum presents the following luminous approach to answer these questions, using the words of the Ramban that the Jewish People would never be allowed to reach such a lowly level where they would be destroyed . Bearing this in mind, the Arizal explains that if the Jewish People would have spent one more moment in Egypt, they would never have been redeemed, for they would have entered the 50th Gate of Impurity . The Ohr Hachaim adds that this is true since they had not received the Torah, but if they would have had the Torah, then they could have even been redeemed from the lowest 50th level.
With this, we can understand why Moshe would ask to borrow from the Egyptians and why he asked for permission to leave Egypt for a short time.
It was already told to Avraham that the Jews would be in slavery for four hundred years . Seeing that they could not survive the remaining time in Egypt without the Torah, Moshe wanted to take the entire Jewish People to Sinai to receive the Torah, which was three days journey away, dressed in the world’s finest splendor as an honour to the Torah that they were to receive - and then to return to Egypt to finish their destined time of slavery!
Moshe had every intention of returning to Egypt and returning their precious items, however, after the final plague, Pharaoh told the Jews to leave and never to return there .
But, in order to explain how the Jews were not required to return the Egyptian’s possessions even though they did not have to return to the land, the Sforno explains that the Egyptians who went on to chase the Jews into the sea were those who lent their gold, silver and clothes and now feared that they would not have them returned. When these Egyptians were finally killed in the sea, the Jews were allowed to keep their possessions, as any victor is permitted to keep the spoil of those who wage battle with them .
Footnotes :
Shemos 5:3 /
Shemos 12:35 /
Tsei Adir /
This was a promise by Hashem after Avraham took Yitzchak to be sacrificed (Bereishis 22:16) /
See the Siddur Arizal and the Haggadah Arizal (פסקא: מצה זו) /
Ohr Hachaim (Shemos 3:8) /
Bereishis 15:13 /
See the Malbim (Shemos 11:1)