The story of Joseph or of Jacob's sons?

We typically read Genesis 37-50 as the story of Joseph, and for good reason. The majority of these stories deal with the trials Joseph faces as he is sold by his brothers into slavery, goes to Egypt, and eventually becomes 2nd in command in Egypt and is able to save his family. We've heard these stories so many times that we just assume that the focus is on Joseph's life. However, then we read stories like Gen. 38 about Judah and Tamar and wonder why the author/editor would place such an unseemly interruption in the middle of the Joseph narrative. Although there are certainly several reasons for the placement of Gen. 38 (it is interesting that clothing plays a prominent role in the three stories of Gen. 37-39), perhaps the placement is due to the fact that this is not simply the story of Joseph.

All throughout Genesis there have been competitions between siblings for blessing and birthright (Ishmael/Isaac, Jacob/Esau, Cain/Abel). The stories at the end of Genesis are no different. Indeed, perhaps it is better to recognize the ending set of narratives as extending back into Gen. 34 and describe the end of Genesis as a tale about the sons of Jacob. With 12 sons, the competition for the blessing/birthright becomes very complicated and interesting given that the reader is expecting a younger sibling to receive it by this point. And, corresponding with expectations, the three oldest sons quickly disqualify themselves in chapters 34 and 35. The process has begun. Then, the oldest son of Rachel is sold into slavery, leaving only the younger at home. It is good to note that the fourth son, Judah, was instrumental in selling Joseph. He should now be out as well.

However, the author then catches us off guard by returning to Judah. Although we should be moving on to the next sons, the story tells the tale of Judah and Tamar. This story seems to function as a lesson for Judah as he recognizes his own faults and repents, claiming that Tamar is more righteous. We then return to Joseph, and then, again we find Judah in the foreground of the story. When attempting to take Benjamin to Egypt, it is Judah who is willing to make a personal sacrifice for the sake of his father and brother. It seems that Judah's heart has done a 180. It is also interesting that this is the second time that Reuben attempts to preserve the family (saving Joseph and protecting Benjamin) and is foiled. It becomes clear that Reuben is still out.

The climax comes when Jacob blesses his sons. Although he gives the birthright to the sons of Joseph, there is still a blessing to be dealt with. So, Jacob proceeds down the line and is begins as expected. Reuben, Simeon and Levi are out because of their sins. But then comes the surprise, Judah receives the blessing and a promise that he will rule over his brothers. Thus, the story of Israel begins--a story that will continue throughout the rest of the Bible. Therefore, perhaps we need to reexamine the end of Genesis and look at the story of all of Israel and not simply at the story of a single tribe.