What did Yaakov mean when he said, "Rav... "?
Rashi and Targum Onkelos: There is much happiness and joy, since Yosef my son is still alive!
Rashbam #1: Enough fainting from disbelief - because Yosef my son is certainly alive!
Rashbam #2, Hadar Zekenim #1, Riva: You say that Yosef is alive and that he rules. It is more than enough that he is alive, irrespective of the fact that he rules.
Targum Yonasan: 'Hashem has performed with me so much good - He saved me from Esav and from Lavan... and I saw much comfort, but that Yosef my son should be alive, that is something that I never dreamt!'
Da'as Zekenim #1: He called the one leading the wagons "Rav." He asked him if Yosef is still alive. He believed him more than [his sons]. 1
Da'as Zekenim #2: The brothers were elaborating about Yosef's greatness. He said "enough" 2 ! If he is alive, I will go and see him.
Hadar Zekenim #2: "Rav" refers to Esav - "v'Rav Ya'avod Tza'ir" (25:23). Esav rejoiced when he heard that Yosef died, for he knew that he will fall only to the children of Rachel. Yaakov addressed him, 'Do not rejoice - Yosef is still alive!'
Ha'amek Davar: It is enough that I know that Yosef is alive, even though I cannot live together with him, and leave Eretz Yisrael. Rather, I will go to see him [and return promptly]. So says Sefer ha'Yashar. 3
If Binyamin returned with them, why would he believe the wagon driver more than Binyamin?! (PF)
Malbim: You need not elaborate about his greatness and power. It is enough that he is alive, that he is my son Yosef. If he were a Rasha, he would not be my son and he would not be my son, and he would not live human life, rather, life of an animal.
Why did Yaakov add that he would go and see Yosef before he dies?
Seforno: He meant that would go down to Egypt to see him, not to live there as Yosef had intimated. 1 Malbim - I will go to see him, and return to Eretz Yisrael.
Ha'amek Davar: "Er'enu" implies seeing briefly, and then returning. Yaakov did not agree to stay in Egypt even for the duration of the famine. He had other thoughts of the famine, like will be explained.
See above, verse 45:10. Also see Ha'amek Davar.
Why is Yaakov called Yisrael in this Pasuk?
Ha'amek Davar: He attained the level of Yisrael, and saw with Ru'ach ha'Kodesh that Yosef persists in his virtue.
