Bereishit (48:8), “And Israel saw the sons of Joseph, and he said, who are these. (48:9) And Joseph said to his father, they are my sons that Elokim has given me here. And he said, please bring them to me, and I will bless them.”
Rashi comments that the Shechinah left Jacob because Ephraim and Menashe would have wicked descendants, and he did not want to bless them. Kli Yakar says that Joseph asked Jacob to bless them in any case, just as HaShem blessed Isaac although Esau would descend from him. But how can Jacob be compared to HaShem? Indeed, Abraham did not bless Isaac because Esau would descend from him (Rashi, Bereishit 25:11).
Isaac, however, did bless Jacob although wicked people would descend from him. The difference between Abraham and Isaac is that HaShem does not establish His Name upon the living, but He did say “the G-d of Isaac” after Isaac became blind (Rashi, Bereishit 28:13). He was therefore able to bless Jacob, at that time.
Jacob surpassed this, as Bereishit (28:21) states, “And I will return in peace to my father’s house, and HaShem will be for me for Elokim.” And Bereishit (33:20) states, “And he set up an altar there, and he called it אל the G-d of Israel.” HaShem was his G-d (without being blind) because he reached the status of אל, as Megilah (18a) explains Bereishit (33:20) that HaShem called Jacob אל. Jacob could therefore bless Joseph’s sons as HaShem could. Jacob therefore said, “please bring them אלי, and I will bless them.” He would bless them with his power of אל. After he blessed them (with his eternal אל), Bereishit (48:21) states, “And Israel said to Joseph, behold I shall die….”
Ta’anit (5a) states that Jacob did not die, but is compared to his descendants; just as they are alive, he, too, is alive. Bereishit (48:16), “And may my name be declared upon them and the names of my fathers, Abraham and Isaac, and may they proliferate abundantly within the land.” Jacob placed his name (first) on them. He placed his אל within them and their descendants. As long as they are alive, Jacob is alive.