John Gill Commentary Genesis 43

And the famine [was] sore in the land .
] In the land of Canaan; it increased yet more and more: this is observed for the sake of what follows, showing the reason and necessity of Jacob's sons taking a second journey into Egypt.

And it came to pass, when they had eaten up the corn which
they had brought out of Egypt
Which, in so numerous a family as Jacob's was, having so many children, grandchildren, and servants, what nine men on so many asses could bring with them must be consumed in a short time, how long cannot be said;

no doubt they lived sparingly on it in such a time of scarcity, to make it last as long as they could, and perhaps only he, his children and grandchildren, might eat of it; the servants, as Calvin observes, might live on meaner food, as acorns, herbs, and roots; and it must not be thought that all this corn was eaten up entirely, and none left, but the far greater part of it, and but very little remaining; or otherwise, how should Jacob, and his sons' wives and children be supported until the return of his sons from Egypt with fresh provisions?

indeed it may be supposed, that the land of Canaan produced some corn, though but little; and it is certain there were other fruits which were serviceable for food, as appears from (Genesis 43:11):

their father said, go again, buy us a little food ;
just enough for him, and them, and theirs, for the present; hoping that the famine would be over quickly, and therefore orders them to go once more to Egypt, and buy some provisions:

they made no motion themselves to go, as it is highly probable they determined they would not, since Jacob had resolved Benjamin should not go, but waited for their father's motion, and which he did not make until necessity obliged him.

And Judah spoke to him Reuben the eldest son has met with a repulse already, (Genesis 42:36); Simeon the next was now in Egypt, (Genesis 42:24), and Levi, perhaps on account of the affair of Shechem, (Genesis 34:25–31), did not yet stand well in his father's favour and affection; wherefore Judah being next, with the consent of his brethren, undertakes to manage the affair with him, who doubtless had an interest in him, as well as authority among his brethren, and was a prudent man, and could speak well.

saying, the man solemnly protested to us; meaning Joseph, though he then knew not that it was he; whom he calls "the man", not by way of contempt, or as thinking and speaking meanly of him, but the reverse, the great man, the honourable man, the governor of Egypt; and so the Septuagint version adds, "the man, the lord of the land"; he in the strongest terms, and in the most solemn manner, protested by the life of Pharaoh:

saying, you shall not see my face; with acceptance, should not be admitted to come near him, or treat with him, and purchase any corn of him:

except your brother be with you; their youngest brother Benjamin.

If you will send our brother with us
Give orders for his going with us, and put him under our care: we will go down and buy you food ;
signifying, on the above condition, that they were ready and willing to take a journey into Egypt, and buy provisions for him and his family, otherwise not.

But if you will not send [him], we will not go down
This they said not as undutiful, and from a spirit of rebellion and disobedience to their father, or of stubbornness and obstinacy, but because they dared not go down, nor could they with any safety; they might expect to be taken up as spies, and put to death as they were threatened; and besides, it would be in vain, and to no purpose, since there was no likelihood of succeeding, or of getting any provision.

for the man said to us, you shall not see my face, except your
brother [be] with you ;
which they repeat both for the confirmation of it, and as an apology for themselves, to clear them from any charge of unfaithfulness.