21. "These are the generations of Jacob: Joseph ..." (Beresheet 37:2). After Joseph settled in Jacob, and the sun - WHICH IS ZEIR ANPIN - mated with the moon - WHICH IS THE NUKVA - he began to produce generations. And who is he that brings forth offspring? The scripture continues saying, "Joseph." For the river that flows and comes out OF EDEN IS YESOD THAT IS DESIGNATED JOSEPH. It is he who is the progenitor of the offspring because his waters never cease to flow!
22. The sun, WHO IS ZEIR ANPIN, unites with the moon, THE NUKVA, but can only bear fruit on the grade that is called 'Righteous,' and on no other grade - NAMELY YESOD. THUS, IT IS CALLED Joseph, who is the grade of Jacob, who can bear fruit and bring forth generations to the world. Thus, it is written, "These are the generations of Jacob: Joseph..."
23. "These are the generations of Jacob: Joseph ..." ANOTHER INTERPRETATION IS THAT anyone who gazed at the facial image of Joseph thought it was the facial image of Jacob. Come and behold, it is not written THIS WAY when referring to any other children of Jacob. FOR EXAMPLE, IT IS NOT WRITTEN, 'These are the generations of Jacob: Reuben ...' OR 'SHIMON' ETC. Only in reference to Joseph IS IT WRITTEN, "THESE ARE THE GENERATIONS OF JACOB: JOSEPH..." THE REASON IS THAT the facial image of Joseph was the same as his father's image.
24. "Joseph being seventeen years old" (Beresheet 37:2). Rabbi Aba said that the Holy One, blessed be He, indicated to Jacob that Joseph was seventeen years old at the time he was lost. All the days that remained AFTER HE REACHED SEVENTEEN YEARS OF AGE, during which time he did not see Joseph, Jacob was crying over him. Because he was crying during those years, the Holy One, blessed be He, gave him another seventeen years, during which he lived in the land of Egypt with happiness, honor, and fulfillment. His son, Joseph, was king and all his sons were there before him. Those seventeen years were considered as life for him. Hence, the text informs us that Joseph was seventeen years of age when he lost him.