John Gill Commentary Genesis 43:3

"And Judah spake unto him, saying, The man did solemnly protest unto us, saying, Ye shall not see my face, except your brother be with you." — Genesis 43:3 (ASV)

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.