What caused Yosef to weep?
Rashi: He wept when he saw that they were genuinely sorry for selling him.
Seforno: He wept because he empathized with their pain. 1
Gur Aryeh: Rashi did not give this interpretation, for why did he cry only now, and not when he first imprisoned them? Rather, he cried upon hearing their remorse.
Why did Yosef distance himself from his brothers before crying?
Rashi: He distanced himself from them so that they should not see him weeping. Ha'amek Davar - He could not reveal himself, for he was obligated to try to fulfill the second dream.
Why did he incarcerate specifically Shimon?
Rashi #1: Because Shimon threw Yosef in the pit; and he said to Levi, "Behold, here comes the dreamer!" (37:19). 1
Rashi #2: To separate him from Levi, to prevent them from plotting against him to kill him. 2
Moshav Zekenim (to 42:22): Yosef intended to incarcerate the oldest. Once he heard how Reuven warned them not to harm him, he did not want to pain Reuven, so he took the next oldest.
Ohr ha'Chayim: Perhaps the brothers themselves chose Shimon (refer to 42:19:151:1).
Malbim: Yosef punished them Midah k'Neged Midah. Just like they suspected him of being a slanderer and Meragel (talebearer), he accused them of being Meraglim. Just like Shimon threw Yosef in the pit with their consent, he incarcerated them for three days and then incarcerated Shimon alone. Just like they sold him for money, he pained them through returning their money in their sacks. Just like they sold him to be a slave, he caused them to say 'we are slaves 3 to my master,' and Yehudah accepted slavery (44:16,33).
Refer to 37:19:1:1; and 37:24:1:1. Ha'amek Davar - Yosef was far away and did not hear when Shimon said so to Levi, but he heard now when they spoke among themselves. Bereishis Rabah 84:16 says that it was because Shimon threw him in the pit.
Rashbam: As they plotted together in Shechem. Refer to 49:7:3:1. Oznayim la'Torah: In any event, even though they were permitted to pick one of them - refer to 42:20:151:2 - he made it easier for them by picking one of them himself.
What are implications of "l'Eineihem?
Rashi: The moment the brothers left Egypt, he took Shimon out and gave to him to eat and drink. 1
Ha'amek Davar: This was Midah k'Neged Midah. They saw Shimon act cruelly to Yosef, and did not protest - now they saw Shimon being incarcerated, and they cannot protest!
Yosef's way of taking revenge - to teach Shimon (and us) a lesson in Midos. (EC)
What did Yosef speak to them?
Malbim: He asked them to pick one of them to be incarcerated, but they were not allowed to, so he had to pick one. Ha'amek Davar - They did not want to, because they accepted Reuven's words, that all of them were equally liable. 1
Malbim, citing Yerushalmi Terumos 8:4: If Nochrim say, give to us one of you (to kill him); if not, will kill all of you, they may not comply.
QUESTIONS ON RASHI
Rashi writes: "It was Shimon that threw him into the pit... Alternatively, Yosef's intent was to separate [Shimon] from Levi, lest they conspire to kill him." Why does Rashi give a second explanation?
Gur Aryeh: Eventually, Yosef would reveal himself to his brothers, and he then makes it clear that he does not want them to think that he bears resentment against them (45:3-8). But now they would likely believe that Yosef still did harbor resentment - for he recalled that Shimon threw him in the pit, and kept only him in prison! Rashi adds that Yosef had another reason for singling out Shimon - to separate him from Levi.
