Мидраш к Берешит 42:1

(Ib. b.) (Gen. 42, 1) And Jacob said to his sons. Why do ye look at one another. Thus said Jacob to his children: "Do not make it appear unto Esau or Ishmael that you are sated, lest they envy you." Ib. 45, 24) See that ye fall not out by the way. R. Elazar said: "Thus said Joseph unto his brothers, 'Do not engage yourselves in Halachik discussions [while on the road], because you may fall out.'" Is this so? Did not R. Ilai, the son of R. Berachia, say that when two scholars travel together on the road and no word of Torah is discussed between them, they deserve to be burnt; as it is said (II Kings 2, 11) And it came to pass, as they went on, speaking as they were going, that, behold, there came a chariot of fire, and parted them both asunder. This is so only because they did speak, but if they had not spoken they would have been burned, [Hence on the road one should study the Torah!] This is not difficult to explain; the latter case refers to the narration of traditions and the former refers to deliberation. In a Baraitha it was explained that Joseph's instructions had the following meaning: You should not march hastily, and bring the sun into town (enter before sunset); i.e., you should not march hastily, for the master said: "Hasty steps take away one-five-hundredth part of a man's seeing; "and bring the sun into town" refers to R. Juda's saying; for R. Juda said: "A man should always leave and enter a town while it is still light; as it is said (Gen. 44, 3) As soon as the morning was light, the men were sent away."

Now Jacob saw that there was corn in Egypt (Gen. 42:1). May it please our master to teach us the number of days during which a mourner is forbidden to work. Thus did our master teach us: A mourner is forbidden to work during the seven days following the burial. However, if he is an extremely poor man, he may return to his labors after the third day to obtain sustenance for himself and the members of his household.

Now Jacob saw that there was grain in Egypt (Gen. 42:1). Scripture states elsewhere in reference to this verse: Happy is He whose help is the God of Jacob (Ps. 146:5). Why does this verse say the God of Jacob and not “the God of Abraham” or “the God of Isaac”? Because the Holy One, blessed be He, stood at the side of Jacob but not at the side of either Abraham or Isaac, as is said: And, behold, the Lord stood beside him (Gen. 28:13).