An argument for innocence
הן כסף אשר מצאנו בפי אמתחתינו השיבנו אליך מארץ כנען ואיך נגנב מבית אדניך כסף או זהב: ויחפש בגדול החל ובקטן כלה וימצא הגביע באמתחת בנימן
Is it not true that we found [your] money in our bags, and we returned it to you from the land of Canaan?! How then could we steal from your master’s home silver or gold?! He began to search [them], starting with the oldest and finishing with the youngest. They found the goblet in the bag of Binyamin
As Yaakov’s sons returned home after successfully retrieving their brother Shimon from captivity, Yosef the viceroy’s men caught up with them. They accused Yaakov’s sons of stealing their master’s special goblet. The brothers were bewildered. They had traveled all the way from Canaan to Egypt, and returned Yosef’s money which had mistakenly been placed in their bags. How preposterous would it be then for them to go ahead and steal a goblet from his palace? Unconvinced by this argument, the viceroy’s men began their search. They started with the oldest brother, and finished with the youngest. Upon opening Binyamin’s bag, they found the goblet. The brothers mourned their providence, and figured they must have been framed. They returned to Yosef’s palace, ready to face the consequences.
There are those that understand that when the Torah says that the viceroy’s men began their search with the oldest of the brothers, its not referring to Reuven, the firstborn. Rather, it’s referring to Shimon, Yaakov’s second son. Where did they get that from? Another question: Rashi felt the need to inform us that the argument of the brothers, that if they returned Yosef’s money why would they steal from him, is one of the ten kal vachomers in the Torah. This is known in logic as an a fortiori argument, where if something less obvious is true, for sure something more obvious is true. It’s surprising that they traveled so far to return the money, so then it’s obvious they wouldn’t steal from Yosef. Why does Rashi feel that we need to know it’s one of the ten? Further, why are there only ten? Surely there are more?
If we analyze carefully the brothers’ kal vachomer, we’ll see that there’s a flaw in it. The brothers were claiming that they traveled all the way from Canaan to return the money that was mistakenly given to them. Is that true? We know it’s true for nine of the brothers. However, Shimon was in jail until recently. He didn’t participate in returning the money. As well, Binyamin didn’t join them the first time they came to Egypt. He had no responsibility to return the money that they had mistakenly brought back with them. What was their argument then?
If we analyze the other kal vachomers in the list that Rashi brings, we’ll notice that they also have a flaw. One of them was stated by Moshe to Hashem. Hashem told Moshe to speak to Pharaoh, and demand he release the Jews. Moshe responded that he is not a qualified spokesperson for the Jewish people. The Jewish people themselves won’t even listen to him, surely Pharaoh won’t listen to him. The problem with this argument is the verse says that the people didn’t listen to him because they were exhausted from their labor. This didn’t apply to Pharaoh. We see then that his argument didn’t start.
However, there is an instance where each of these kal vachomers are valid. With regards to Moshe’s argument to Hashem, he mentioned the Jewish people didn’t listen to him. This statement included even the tribe of Levi, who as the Priestly class, weren’t enslaved in Egypt. We see that even they didn’t listen to Moshe, even though they weren’t exhausted from labor. It was this tribe that Moshe had in mind when he said that the Jewish people didn’t listen to him. All the more so Pharaoh wouldn’t listen to him.
The same is true with the argument of the sons of Yaakov. They said that they had traveled all the way from Canaan to return the money that wasn’t theirs. It’s true, this argument didn’t apply to Shimon and Binyamin, as they weren’t involved in the first trip home from Egypt, when the mistake occurred. However, it did apply to the other nine brothers. They were saying that if these brothers went to so much effort to return what was not theirs, all the more so would they not steal something from the palace. Rashi is bothered that these two arguments have some sort of flaw. He wants us to realize that this isn’t so difficult, as there are ten instances of kal vachomers in the Torah that have a flaw. He is stressing that despite this flaw, there is indeed some resolution to the argument.
Perhaps the unique explanation that the viceroy’s men started their search with the oldest, meaning Shimon, and ended with the youngest, meaning Binyamin, was motivated by this issue. These two brothers were the only ones who didn’t have an argument for innocence. They weren’t involved in the mistake with the money, and had no proof that they weren’t guilty. As such, the verse is really telling us that the viceroy’s men only searched these two brothers. The older one, Shimon, and the younger one Binyamin. The others weren’t searched, as they had a kal vachomer proving their innocence.
 Based on Maharil Diskin to Genesis 44:12 s.v. בתרגום and Sichos Kodesh 5736 parshas Mikeitz § 30-34 (p. 331-333), by the Lubavitcher Rebbe zt”l, summarized into Hebrew from Yiddish in Biurei HaChumash to v. 8
 Genesis 44:8,12
 The Maharil Diskin says this explanation is from רבותינו ז”ל, which sounds like he’s referring to Chazal. The Brisker Rav in Chiddushei Maran HaGriz Soloveitchik Torah § 38 says it’s a Midrash, brings the words of the Maharil Diskin, and then concludes that we don’t know where this Midrash is. Da’as Mikra to v. 12 fn. 2 says this idea is from the Beis HaLevi to v. 5, but I couldn’t find where he mentions it. Further, The Brisker Rav, a grandson of the Beis HaLevi, surely would have mentioned that his grandfather discusses it. In Chiddushei Maran HaGrach Kanievsky parshas Mikeitz § 5, it is brought that Rav Chaim Kanievsky shlita was asked where this Midrash is, and he responded איני זוכר
 Cf. Targum “Yonasan” to v. 12 who explicitly writes that they started with Reuven. The Maharil Diskin suggests it was to reject this alternate explanation
 Maharil Diskin
 Rashi to v. 8
 Bereishis Rabbah 92:7
 Sichos Kodesh
 Sichos Kodesh only mentions Binyamin, but Maharil Diskin mentions them both. As will be evident, each one mentioned what they needed in order to answer their question
 Sichos Kodesh. See there where the Rebbe explains the flaw for two more in the list
 Exodus 6:12
 V. 9
 Sichos Kodesh points out that Rashi only cites the ten kal vachomers in these two instances. He explains this is because Rashi is bothered by these two more than the other instances, as the flaw is so apparent. Rashi therefore says don’t be bothered, because if you look in the list, you’ll see they all have a flaw. At the same time, despite their flaws, these two have some instance in which they’re logically sound, as will be explained
 Rashi to Exodus 5:4, quoting Shemos Rabbah 5:16
 Maharil Diskin. Da’as Mikrah loc. cit. also says the Beis HaLevi explains it this way (but as mentioned in note 3, I couldn’t find it. Perhaps the editor was thinking of the Maharil Diskin, brought by the Beis HaLevi’s grandson, the Brisker Rav)