Why did Yaakov say that his wife bore to him only two sons, and only one survived? He had many other sons from his other wives!
Ramban: Yaakov was pointing out that the only wife he had married of his own accord was Rachel. 1 Consequently, he loved the two sons whom she had borne him like real sons, while his other sons he considered like sons of concubines. Consequently, now that his brother was no longer alive, Binyamin was the primary son whom he loved. 2
Indeed, the Torah always places Rachel before Leah (Refer to 31:4:1:1). And, as the commentaries point out, that explains why, later in the Parshah, the Torah refers to Rachel as "the wife of Yaakov" (46:19) (Ramban).
It is remarkable that Yaakov told this to his sons, and that Yehudah (Leah's) son, was now quoting his father - without the least bit of malice. (EC)
Here, it is implied that it was after Yaakov said, "go buy a little food for us" (44:25), that he said that Binyamin may not go. Above, first Yaakov said "my son will not descend with you" (42:38), and afterwards "go buy a little food for us" (43:1)! Why did Yehudah reverse the order? Why does he add "Tarof Toraf" (44:28)?
Ha'amek Davar (to 44:27-28): After Yaakov agreed to rely on Yehudah to be a guarantor, and send Binyamin, he added to be careful also about something that one would never think to be careful about it (e.g. being torn via a beast). Also the episode with the cup, one cannot think that he really stole it, but it is like being torn (i.e. even so, I am responsible for it).
