As Yaakov makes his way to Egypt to reunite with his son, Yosef, God appears to him in a prophetic vision and offers him encouragement. Among the promises the Almighty makes to Yaakov is, "Yosef will place his hand over your eyes" ("ve-Yosef yashit yado al einekha" - 46:4). What does this mean?
Several different interpretations appear in the commentaries. Perhaps the most straightforward understanding is to view the term as a euphemism for Yosef's provision of all Yaakov's needs throughout his years in Egypt. The Rashbam, Seforno and Chizkuni (in his second approach) interpret along these lines, only they differ in the way they extract this meaning from the words. Seforno explains that Yosef's efforts on his father's behalf will absolve Yaakov of the need to "open his eyes" to supervise his affairs. Throughout his years in Egypt, Yaakov could "keep his eyes closed," enjoy a worry-free life as his son cares for all his needs. The Rashbam and Chizkuni, by contrast, reread the word "einekha" (your eyes) as "inyanekha" - your affairs. This phrase thus means that Yosef will pay full attention to all of Yaakov's concerns.
Another group of Rishonim adopt a much different, more literal approach, one which appears as early as in the commentary of Rav Sa'adya Gaon. Rav Sa'dya cryptically writes, "He will close your eyes." Meaning, Yosef will perform the customary ritual by which a son closes his father's eyes immediately after his death. God thus informs Yaakov that Yosef will attend his death. The Ibn Ezra, Radak and Chizkuni (in his first approach) follow this explanation in their respective commentaries.
This interpretation, of course, raises the question as to the significance of Yosef's closing his father's eyes. What does this represent, and why must God inform Yaakov of his son's presence at his death? Two different possibilities within this general approach appear in the commentaries. The Chizkuni explains this promise to mean that Yosef will ensure the return of Yaakov's remains to Eretz Canaan for burial there. This accommodates the explanation given by the Chizkuni and many others - including Rashi - of the immediately preceding clause in this verse: "… and I will surely bring you back." According to many Rishonim, God here guarantees Yaakov of his burial in Canaan. It stands to reason, then, as the Chizkuni explains, that the following clause - "Yosef will place his hand over your eyes" - relates to that promise.
The Radak, however, takes a different approach. God guarantees Yaakov that Yosef will not only tend to his needs, but will remain in power after Yaakov's death to support Yaakov's children and grandchildren.
We conclude with one final interpretation of this verse, along the lines of "derush," by Rav Yeshaya Ehrenfeld (a grandson of the Chatam Sofer), in his work, "Shevet Sofer." As several commentators explain, as he traveled to Egypt Yaakov felt concerned over the spiritual well-being of his family. What kind of relationship will develop between Benei Yisrael and the Egyptians? Will they remain distinct? Will they retain their identity even while their interact with the Egyptians on all different levels? If they assimilate too thoroughly, will they ever make it back to Canaan to fulfill their national destiny?
God therefore promises him, "I will descend with you to Egypt, and I will surely bring you back." The presence of God will accompany Yaakov and his family in Egypt, ensuring their distinctive identity and eventual return to Canaan. Moreover, "Yosef will place his hand over your eyes." Rav Ehrenfeld suggests that Yosef will serve as a source of comfort, assuaging Yaakov's fears. The fact that Yosef has remained loyal to his past and the teachings of the patriarchs even while ascending to the peak of the Egyptian bureaucracy will reassure Yaakov that with the Almighty's help, his offspring will retain their Jewish identity even in the spiritually hostile environs of Egypt, and they will ultimately return to the land of their forefathers.