Bava Batra 123 - Shabbat October 26, 24 Tishrei

How is the double portion calculated - two times a portion that all the other brothers get or two-thirds of the whole property? The answer is derived from several verses and the Gemara explains why all are necessary. Many of the proofs are from Yosef's double portion.  Why did Yaakov take the double portion from Reuven and give it to Yosef? First, it should have been given to Rachel's son, (as is derived from Breishit 37:2), but Leah was worthy that her son be the firstborn because she pleaded for mercy. However, on account of Rachel's tzniut, it was returned to her son. To explain the mercy of Leah and the tzniut of Rachel, the Gemara elaborates in great detail on the story of how Yaakov wanted to marry Rachel but ended up first marrying Leah.  A braita describes various things of which the firstborn receives a double portion and the Gemara explains each case.