Why the Jewish people did not receive the Torah until after the Egyptian exile:^[1]

It remains to be understood why the Jewish people were given the Torah so late in history, and as to why it was not given to the forefathers. Did the Jewish people not already merit the Torah in the days of our forefathers? The explanation is as follows: The Torah existed prior to it officially being given to the Jewish people on Sinai, however, prior to it being officially handed to the Jewish people it could only be fulfilled on a mystical and spiritual level. Accordingly, although our forefathers fulfilled the entire Torah prior to it being given, they only fulfilled the spiritual correspondence of the Mitzvah’s and did not fulfill it in its physical sense. They were able through their actions to draw down G-dliness internally, within the spiritual worlds, but not externally into the physical world. The one exception to this was the Mitzvah of circumcision, which was gifted to Avraham to be fulfilled in the physical sense, in order so Yitzchak would be born in holiness. Now, in order for the Torah and Mitzvahs to be drawn down to the physical world and be fulfilled with physical objects and thereby imbue those objects with G-dliness it became necessary for them to go through the Egyptian exile. The bitterness of the Egyptian exile and the laborious work that the Jewish people had to perform is what allowed the Torah to be drawn down from a much higher level, so it then be able to descend to a much lower level, within the physical world. In other words, our forefathers only were able to access the Torah as it existed within Seder Hishtalshlus, and for this reason they were unable to draw it down into the physical world which is below Seder Hishtalshlus. However, the Jewish people through the Egyptian exile were able to access the Torah as it exists above Seder Hishtalshlus and were hence able to draw it down to below Seder Hishtalshlus, to within the physical world.

[1] Torah Or 11b