“And G-d said to Israel in a night vision, ‘do not be afraid to go down to Egypt, for I will turn you into a great nation there; I will go down with you to Egypt, and I will also bring you up, and Yosef will place his hand on your eyes” (B’reishis 46:3-4). Obviously, even after hearing that Yosef was a ruler over Egypt, Yaakov was concerned about going down to see him. He therefore brought offerings to G-d in B’er Sheva, (near) where G-d had told Yitzchok not to go down to Egypt (26:2) even though there was a famine in Canaan then too, hoping to receive a divine message either that it was okay for him to go to Egypt or that he shouldn’t. G-d responded by telling Yaakov that he should go, adding that “Yosef will place his hand on your eyes.” What was G-d telling him by adding these words? Was it that integral to alleviating Yaakov’s concerns about leaving Canaan and going to Egypt? What do these words even mean?
There are two basic approaches among the commentators explaining what “putting his hand on your eyes” means. Some (e.g. Rashbam, B’chor Shor) say the expression refers to Yosef taking care of all of Yaakov’s needs. However, as the Netziv points out, Yosef’s message to Yaakov explicitly included taking care of him (45:11), so there doesn’t seem to be a need for G-d to reassure Yaakov about this. S’fornu takes the expression more literally; Yaakov won’t need to keep his eyes “open” in order to make sure that he and his family will be properly supported, as Yosef will take care of everything, thereby freeing Yaakov from having to associate with anyone or anything Egyptian, allowing him to focus solely on his spiritual growth. Shir M’on (Rav Shimon Sofer, the son of the K’sav Sofer/grandson of the Chasam Sofer) extends it beyond being supported; Yosef will use his position (his “hand”) to carry out Yaakov’s vision (his “eyes”), providing everything needed to build a nation that will carry out the mission started by our forefathers.
Others (e.g. R’ Saadya Gaon, Ibn Ezra) explain that when someone dies with his eyes open, a son will manually close them; G-d was telling Yaakov that Yosef will do this for him, i.e. be with him when dies. The question then becomes what significance this has, and why it was important for Yaakov to know this before going down to Egypt. Chizkuni says G-d was letting him know that Yosef would be able to use his position as Viceroy to ensure that Yaakov could be brought back to Canaan for burial (see B’reishis Rabbah 94:6). Or HaChayim suggests that telling Yaakov that Yosef would be there when he died was a polite way of saying that Yaakov must remain in Egypt for the rest of his life. Radak combines the two approaches (Yosef supporting Yaakov and being there when Yaakov dies), and positions it as if Yaakov’s concern was not whether Yosef would support him, but whether Yosef would be around to support the family even after Yaakov’s death. By telling him that Yosef would still be there to “close his eyes,” Yaakov could now be confident that Yosef would support them afterwards as well. Another way to combine the two approaches is by having the expression “Yosef will put his hand on your eyes” refer to one end of the time-frame of Yosef’s support; G-d was telling Yaakov that Yosef will take care of him for the rest of his life, up to and including Yaakov’s death (similar to how some understand teaching the wise son about not eating after the Afikoman to mean teaching him all the laws of the Seder up to, and including, the very last one). But there may be more to the story.
The 22 years Yosef was missing (and presumed dead) were very hard on Yaakov; it was only after he finally believed that Yosef really was still alive that his “spirit lived” (45:27). Even if things had stabilized in the years after Yaakov was shown Yosef’s bloody robe, over the last two years things had worsened. First Shimon was taken prisoner by the Egyptian government as his sons were accused of being spies, then, despite being told how traumatic it would be for their elderly father, the Viceroy insisted that Binyamin must be brought down to Egypt as well. What a wicked person this Egyptian Viceroy must be! Then Yaakov finds out that the “wicked Viceroy” is none other than his own long-lost son, Yosef! How could his own son put him through such an ordeal? If he was the Viceroy, why didn’t he send word to his worried, bereaved father that he was alive and well (see page 2 ofhttp://www.aishdas.org/ta/5767/miketz.pdf)? Even if Yosef wanted to (chas v’shalom) get even with his brothers, how could he do those things to his father? Was Yosef upset at his father too? Did he blame his father for sending him to check on his brothers knowing that they hated him? Did Yosef become so assimilated in Egypt that he would try to torture the family that had turned on him? Was his insisting that Yaakov move down to Egypt the end of this long ordeal, or just the next step of a plan to continue to torment him? We (with the possible exception of Rav Yoel Bin Nun, seehttp://www.torah.org/advanced/mikra/5757/sup/sup.vayyigash.1.html) may know that Yosef didn’t blame his father, and therefore would never do anything to hurt his father (or brothers) if there was another option, but how could Yaakov know?
It is therefore possible that Yaakov was not only concerned about leaving the Holy Land because of a famine (since his father was told not to), about staying connected with G-d while in Egypt, about eventually returning to Canaan, and about his family assimilating into the Egyptian culture (see Malbim), but he was also concerned that perhaps Yosef’s “invitation” was just the next stage of his ongoing torment of the family he thought had abandoned him. Therefore, when G-d gave Yaakov permission to go see Yosef in Egypt, He also reassured him that He would be there with him, would bring him back, that his family would become a great (and distinct) nation there, and that Yosef would help him until the day he died. By telling him that “Yosef will put his hand on your eyes,” G-d was reassuring him that this was not a trap, as Yosef would support him, now and forever, even after Yaakov’s death.