Jamieson, Fausset and Brown on Genesis 42:6

6. Joseph was the governor--in the zenith of his power and influence.

he it was that sold--that is, directed the sales; for it is impossible that he could give attendance in every place. It is probable, however, that he may have personally superintended the storehouses near the border of Canaan, both because that was the most exposed part of the country and because he must have anticipated the arrival of some messengers from his father's house.

Joseph's brethren came, and bowed down themselves before him--His prophetic dreams [Ge 37:5-11] were in the course of being fulfilled, and the atrocious barbarity of his brethren had been the means of bringing about the very issue they had planned to prevent (Is 60:14; Re 3:9, last clause).