Yaakov decides to bless his sons before he dies and begins with Reuven, the first born and son of Leah. Yaakov declares: "Reuven you are my firstborn" (49: 3). At first, this sounds reasonable. We might think that Reuven was being reassured as if to say, "You Reuven, despite the experiences with your brothers and despite Yosef's privileged role, are still my first born. You deserve the benefits that accrue to the first born."

However, this is not Yaakov's point. Yaakov intends to say: "You are the first born, but you will receive none of the benefits that usually accrue to the first born." Reuven will not receive pi shenayim (a double inheritance), nor will you become a kohen (a status granted to first born sons before the transgression of the golden calf).

Yaakov has already transferred the right of the first born (inheritance) to Yosef. In a previous verse Yaakov declares:

"Behold, I am about to die. G-d will be with you and will bring you back to the land of your fathers. I have given you, one portion more than your brothers, which I took from the Amorite, with my sword and with my bow" (48: 22).

While it is difficult to determine what historical event is being referred to (when did Yaakov fight such a war?), the intent is clear. Yosef will receive twice as much.

Rashi offers two explanations of the verse. First, that the reference is to "when Shimon and Levi killed the people of Shechem." Alternatively, Yaakov is referring the rights of the firstborn. Only he receives two portions, and Yaakov is giving that privilege to Yosef.

Yaakov has already made this point in another way: "Now your two sons, born in Egypt. they are mine; Efraim and Menashe shall be mine like Reuven and Shimon" (48: 5).

Rashi explains: they will be counted with my other sons and take their own portions in the land of Yisrael. They will each be treated as one of my sons.

[We will not deal at this time with how this deal was better than simply giving Yosef a double share of in the land but under a single banner: one enlarged territory for Yosef rather than two shares, one for Ephraim and one for Menashe.]

However, Rashi's intention is to indicate that Yosef was receiving the privilege of the first born and that Reuven had lost that opportunity.

The verse is to be understood as follows: "Reuven even though you are the first born, you have lost that status and the advantages in inheritance will go to Yosef."

For Yaakov it was important to stress at the end of his life that all of his sons would be part of the new nation that was in formation. Regardless of what they had done in the past they would remain part of the covenanted people and would carry the sign of circumcision indicating that their role was determined. (We circumcise children when they are eight days old; when they still do not have the wherewithal to determine whether they are interested in being part of the covenant or not. This decision is made by the father and cannot be rescinded.) However, this was not the case for special privileges like the double inheritance or the priestly designation. In these arenas the sons had to prove themselves. Reuven did not deserve the inheritance and lost it to Yosef. Eventually the first born were replaced by the tribe of Levi who became the tribe of priests and served in the Temple.