Tafsiran Kejadian 42:3: Rashi, Sforno, Or HaChaim & Radak

וירדו אחי יוסף AND JOSEPH S BRETHREN WENT DOWN — It does not call them “the sons of Jacob” (as in 5:5), thus suggesting that they regretted having sold him and that they had made up their mind to behave towards him in a brotherly manner and to redeem him at whatever price people might fix for them to pay (Midrash Tanchuma, Miketz 8).

וירדו אחי יוסף עשרה, the official selling grain in Egypt did not sell to more than one family per buyer. The reason for this restriction was intended to ensure that the buyers would not resell some or all of what they had bought, thus using what Joseph had stored as a source of enriching themselves.

אחי יוסף, Joseph's brothers. The reason they are described as Joseph's brothers instead of as Jacob's sons is that at that time they were determined to perform the brotherly act of redeeming him out of slavery.

עשרה TEN — What is the mention of this number intended to tell us? Is it not written (Genesis 42:4) “but Benjamin, Joseph’s brother did he not send” (and we therefore know that only ten brothers went to Egypt)? But it means to suggest that so far as their feeling of brotherhood towards Joseph was concerned they were divided into ten, because the love and hatred that all of them bore him were not alike, where as in regard to buying corn they were at one and united (Genesis Rabbah 91:2).