Why did the man change his stance in the middle, first agreeing with the brothers' suggestion and then suggesting something else?
Rashi, Seforno and Rashbam: Strictly speaking, he told the brothers that they were right - if a theft is discovered among a group of ten men, they are pronounced guilty. 1 However, he would go beyond the letter of the law, taking only the culprit as a personal slave (instead of the death-penalty), and allowing the rest to go free. 2
Ramban #1: Based on the fact that, following the man's accusation that they were all guilty of the theft, the brothers drew a distinction between the sentences of the thief and the brothers, it was clear that they were not aware of the crime, and that their volunteering to become slaves was in the form of a penalty. And what the man therefore meant was that, based on their explanation, that only the thief was guilty and they were innocent, he would take the thief alone as a slave, 3 and allow them to go free.
Ramban #2: Alternatively, he meant to say that, unlike their claim that they were innocent, and that they penalized themselves to become slaves, they were obligated by law to be incarcerated until it became clarified that they were indeed innocent. 4
Da'as Zekenim: Indeed, returning the money shows that you are trustworthy - but Binyamin (and Shimon - Hadar Zekenim) did not return anything. He (Hadar Zekenim - or Shimon) stole it without your knowledge! 5
Rosh, Moshav Zekenim: I will do like your words ("we are slaves") to the thief [and not kill him]. Hadar Zekenim - I will also be lenient and totally exempt the others.
Ohr ha'Chayim #1: I accept your proof that if you returned money, surely you would not steal now - however, this does not justify the thief! The thief should die; he will be my slave until I want to kill him.
Ohr ha'Chayim #2: You said that the thief should die. This is if witnesses saw him steal. When the theft is found with him, he is liable due to the law of the kingdom. The rest of you are established to be honest, and there is no testimony against you.
Malbim: I accept your proof that if you returned money, surely you would not steal now. Also now, the money is missing; surely it will be found in your sacks! One of you is a thief, i.e. the one who has the cup; he stole the money both the first time 6 and now. You are innocent, also for the money.
Ha'amek Davar: You are correct. Even if it is found with one of you, there is no suspicion on the others. Therefore, only the thief will be my slave - like [is proper for] a Stam thief, and not one who stole from the king's house.
Rashbam: As is customary among businessmen. Moreover, bearing in mind the fact that it was the goblet of the ruler who was so good to them in that he returned their money, they all deserved the death-penalty - Seforno).
Since, although they were all together when the goblet was found, they may well not have been involved - as they claimed, and what he wanted was payment for the theft, not the death-penalty. The Ramban refutes Rashi's explanations, because, according to Rashi, the words "Gam ... Kein Hu" do not fit well (though he attempts to explain them in different ways; also see Gur Aryeh - 44:10:1.1)
As the Midrash specifically states.
If presumably, Binyamin stole it, why did he begin searching from the oldest? Rashi (to 44:12) said that he did so lest it not seem that he knows who has it! (PF)
Is not "la'Asher Al Beiso" (44:4) who chased after them, the same "Ish Asher Al Beis Yosef" (43:9) who told them, "I received your money; your G-d... returned it to you"?! And even if he is not, they could say 'go ask the "Ish Asher Al Beis Yosef" about the first money!' Perhaps he meant, now that the current money was stolen back, I realize that also the first time, the thief stole it back after I received it, and returned it to you. (PF)
Why did the man say "you will be a slave to me"? He should have said "you will be a slave to my master"!
Da'as Zekenim, Moshav Zekenim: [The man] needed to pay for [loss of] all the Kelim over which he was appointed. (Therefore, it is as if the thief stole from him.)
Ha'amek Davar: He was repeating Yosef's words. 1
Presumably, this refers to these words, but not "Gam Atah k'Divreichem." Did Yosef know what his brothers will say?! (PF).
Why does it say "Aved" with a Kamatz, and not "Eved"?
Ha'amek Davar: If the word was Sof Pasuk, this would change the Segol to a Kamatz. This was the final Mishpat (only the thief is a slave, and there is no claim at all against the others 1 ), so it is treated like Sof Pasuk.
I.e. do not say that there is a charge against the others, just my master will be gracious and exempt them. (PF)
QUESTIONS ON RASHI
Rashi writes: "'Even now; as per your words' - Even [though] what you have proposed is correct justice - if one of a group is caught with a stolen item, the entire group is held [accountable] - and yet, I will be more lenient with you...." Ramban asks - If so, why did the viceroy later express horror at the idea that they all be held culpable, "Chalilah for me to do such a thing!" (44:17)?
Mizrachi: In 44:17, the viceroy was not saying, 'it would be a disgrace for me to hold you as slaves' [for this] - for such a verdict would in fact be justified! Rather, he meant 'Chalilah for me to suspect you of being accomplices to the theft.'
Gur Aryeh: The viceroy was responding to what the brothers had said; "G-d has found [our] sin, [so] let us all be slaves to [you]" (44:16). They said, 'we know our innocence (Rashi loc. cit.), yet despite that, take all of us as slaves!' He responded, 'Chalilah for me to punish you without sin,' merely at your own request! I chose not to be so exacting in your judgement; I do not consider you accomplices to Binyamin; but rather that he acted alone.
