Midrash sobre Génesis 44:3

(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."