Isaac's Wells and the Books of the Torah

How many wells did Isaac our father dig in Beersheba? Rabbi Yehudah son of Rabbi Simon said: four, corresponding to which his descendants became four banners [encampments] in the wilderness. And the Rabbis say: five, corresponding to the five fifths of the Torah [the five books]. "And he called the name of the well Esek" (Genesis 26:20) corresponding to the book of Genesis, in which the Holy One, blessed be He, occupied Himself [nit'asek] and created His world. "And he called its name Sitnah" (Genesis 26:21) corresponding to the book "And these are the names" [Exodus], on account of "and they embittered their lives" (Exodus 1:14). "And found there a well of living water" corresponding to the book of Leviticus, which is filled with many laws. "And he called it Sheva" [seven] (Genesis 26:33) corresponding to the book of Numbers, which completes [the count] to seven fifths of the Torah. But are they not five? Bar Kappara treats from the beginning of the book of Numbers until "and it came to pass when the ark set out" (Numbers 10:35) as one book; "and it came to pass when the ark set out" and the verse after it [Numbers 10:35-36] as a book in itself; and from there until the end of the book as a book in itself. "And he called its name [Rehoboth]" (Genesis 26:22) corresponding to Deuteronomy [the Second Torah / Mishneh Torah].