Musar sobre Exodo 12:40

Here is an instance that shows that the sequence in which the Torah reports events is not necessarily the chronological order in which things occurred. Remember that Abraham was seventy years old at the time of the covenant between the pieces in 15,18 (as we know on the authority of סדר עולם). Our sages also consider the count of the four hundred years that the Torah mentions in that covenant (15,13) as commencing with the birth of Isaac. When Exodus 12,40 mentions a period of 430 years that the Israelites "resided" in Egypt, our sages compute that period as having commenced at the ברית בין הבתרים "the covenant between the pieces," i.e. when G–d revealed Himself to Abraham in 15,1. [Rashi's commentary that this number includes the years spent elsewhere as strangers by Abraham and his descendants, may be based on the letter ו (and), before the word מושב in 12,40. Ed.]

In 45, 23 Joseph hinted to his father that he should come down to Egypt to him to be exiled, seeing that the previous זקן, Abraham had chosen this path, and that this path had been approved since the six days of Creation, i.e. since the time of the יין ישן. It is interesting to note that the numerical value of the words יין ישן, equals the total number of years that the Jews experienced exile both in Egypt and other countries. This is described in Exodus 12, 40. The immediate cause for this was Joseph, because he was the בן זקונים, etc.

Having this in mind, we can understand an enigmatic Midrash Rabbah Genesis 63,3 on this פרשה: "These are the descendants of Isaac the son of Abraham, Abraham begat Isaac. Abraham was called Abraham; Isaac was called Abraham for the Torah says "these are the descendants of Abraham, Abraham." Jacob's name was called Israel because the Torah says in Genesis 32,29: "He said to him: 'Your name will no longer be called Jacob but Israel.' Isaac was called Israel, as the Torah says in Exodus 1,1 'And these are the names of the children of Israel who came to Egypt with Jacob.' Abraham is called Israel." Rabbi Natan added that there is a profound meaning in: ומושב בני ישראל אשר ישבו במצרים ובארץ כנען ובארץ גשן שלושים שנה וארבע מאות שנה. "The period that the children of Israel lived in Egypt, Goshen and Canaan respectively prior to the Exodus was 430 years."