Ge 35:16 Then they journeyed from Bethel. And when there was but a little distance to go to Ephrath, Rachel labored in childbirth, and she had hard labor.

17 Now it came to pass, when she was in hard labor, that the midwife said to her, "Do not fear; you will have this son also."

18 And so it was, as her soul was departing (for she died), that she called his name Ben-Oni; but his father called him Benjamin.

19 So Rachel died and was buried on the way to Ephrath (that is, Bethlehem).

20 And Jacob set a pillar on her grave, which is the pillar of Rachel's grave to this day.

21 Then Israel journeyed and pitched his tent beyond the tower of Eder.

22 And it happened, when Israel dwelt in that land, that Reuben went and lay with Bilhah his father's concubine; and Israel heard about it. Now the sons of Jacob were twelve:

Moses here is explaining to his original Israelite readers as to why the tribe of Benjamin received the land inheritance they had and why the tribe of Reuben forfeited the leadership in Israel. Between Bethel and Ephrath-Bethlehem lie the territory of the tribe of Benjamin. Why was the tribe given this part of the Promise Land? Because Benjamin was born there. Rachel, Benjamin's mother who gave birth to him there, died and was buried there.

 1 Sa 10:2 "When you have departed from me today, you will find two men by Rachel's tomb in the territory of Benjamin at Zelzah..."

Reuben was the firstborn of the tribes of Israel. He should have received the leadership of the tribes but that was given to Judah. Why? Reuben forfeited this privilege because of what he did here "... Reuben went and lay with Bilhah his father's concubine..."

Simeon and Levi, both the second and third son's respectively, were bypassed because of their violence and treachery at Shechem. The privilege went from the first son to the fourth son, Judah.