Why did Jacob adopt Joseph's sons?

[JTB.SDG]

In Genesis 48:5-6, Jacob tells Joseph he is adopting his sons, which is then formalized by symbolically placing them on his knees (v12; cf. 30:3,6).

But why does he do this? My best guess is that it is somehow related to giving Joseph a double portion among his sons (v22); if he adopts Joseph's TWO sons, Joseph's descendants will end up having a double portion as having two tribes represented among the twelve in Canaan. Anyone have any thoughts on this?

Incidentally, it seems Joseph does the same thing with his grand children (50:23).

 

[Contra_Mundum]

It does seem as though the birthright and the blessing are divided in Jacob's sons. Joseph receives the double-portion, and that through two of his sons being "adopted" by Jacob into equal standing with Joseph's brothers. Joseph is quite literally beyond any measurable gift his earthly father could give him materially.

Even if he was given the entirety of Jacob's estate, all the other sons being disinherited for cause (ala Ishmael), it would be a drop in the bucket of Joseph's owned/possessed power and glory. In this, we see even clearer the type Joseph is of Jesus' ascendant glory.

To Judah falls that blessing, which in earthly terms is the mantle of spiritual leadership, to the head whereof attends the covenant promise that will flow to all the members. It was Judah--great sinner that he was--who led the family after Joseph's "disappearance," but also led them in contrition and repentance. He was willing to lay down his life for Benjamin;, he led all the brothers in volunteering to all "die" for Benjamin's release. He had become the spiritual leader of the family.



*It is not obvious to me how Joseph "does the same thing" with his grandsons.

 

[timfost]

Here's the safe answer:

What Bruce said.