Is it dignified for a man as important as Yosef, to sell grain to every common Tom, Dick and Harry?
Ramban #1 (citing the Midrash), Ohr ha'Chayim, and Targum Yonasan: Anticipating the arrival of his brothers to purchase grain, he ordered the closure of all the storehouses other than his own. 1
Ramban #2: He did not actually sell grain. He oversaw the purchases by checking the buyers' credentials and instructing the seller to go ahead with the sale, and how much of each species to sell them.
Seforno: Because of the vast sums of money that were being collected on behalf of Pharaoh, 2 Yosef did not trust his servants, and gave instructions that nobody could purchase grain without his personal stamp or signature.
Targum Yonasan: And that his officers take down the names of all the purchasers and their fathers that came on that particular day and hand the list to him. He then proceeded to serve the purchasers personally. Consequently, after receiving the lists that contained his brothers, they all appeared before him to buy grain. And this explains the connection between the beginning of the Pasuk and the end.
See Bereishis 47:14.
Why does the Torah repeat the fact that they were Yosef's brothers?
Targum Yonasan: Because they spread out to search for him in all the streets and market-places. 1
Malbim: This hints to fulfillment of the first dream when they bowed to him.
What is the significance of Hishtachava'ah (as opposed to other expressions of bowing down)?
Rashi #1: It means that they stretched themselves flat on the ground. 1
Rashi #2: It conforms to Yosef's dream in Bereishis (37:7), where the same word is used. 2
Based on the Gemara in Shevuos (16b), which also defines 'Kidah' as on the face and 'Keri'ah' as kneeling (See also Rashi to Bereishis 43:28).
Why does it say that Yosef was the Shalit (ruler)?
Hadar Zekenim: It is because he was Sholet over his Yetzer.
Oznayim la'Torah: To demonstrate how Yosef had the power to issue the decrees that forced all the brothers to come to [the city of] Mitzrayim - in order to stand and to bow down before him, 1 and to accuse whoever he did not take a fancy to of being a spy.
