Commentary for Genesis 46:19

בני רחל אשת יעקב THE SONS OF RACHEL, JACOB’S WIFE — In the case of all the other wives of Jacob the term אשת “wife” is not mentioned. But the reason is because she was the chief mistress of the household (Genesis Rabbah 73:1).

בני רחל אשת יעקב, who had been the wife whom he had wanted to marry. She had also become the mother of Joseph and Binyamin, the choicest of the tribes as mentioned by our sages in Sotah 36. The text there is: “Joseph by himself was worthy enough to have produced 12 tribes just as his father Yaakov.” The same sages, in Shabbat 55 are on record as saying that Binyamin died only because death had ben decreed for every member of the human race.” [not because he had committed any personal sin which would have accounted for his forfeiting eternal life. Ed.]