What happens next is one of the great speeches in the Hebrew Bible. Judah steps out of the huddle of brothers and walks directly toward the vizier — the man he still believes is an Egyptian ruler, a man who has just offered to enslave Benjamin.
"Judah came near to him and said, In imploring my lord, let thy servant, I implore, speak a word in the hearing of my lord, and let not thy anger grow strong against thy servant; for at the hour that we came to thee thou didst say to us, I fear before the Lord; and now thy judgments are rendered like (the judgments) of a prince of Pharoh" (Genesis 44:18). Targum Pseudo-Jonathan preserves the opening with surgical precision.
Read the accusation hiding under the politeness. The vizier once told the brothers, ani et ha-Elokim yarei — "I fear God" (Genesis 42:18). Judah is now holding him to that claim. You said you feared God. Then why are you behaving like a typical prince of Pharaoh, snatching a boy because of a cup?
The sages read this as tokhachah — legitimate rebuke, spoken with the body bent in implored courtesy but with the words aimed straight at the conscience of the ruler. The Aramaic rabrava de-Pharoh, "a prince of Pharoh," is Judah's way of saying: you have become exactly what you said you feared to become.
This is not the Judah who sold Joseph. That Judah calculated profit. This Judah calculates justice. He walks toward the throne of Egypt, unarmed, outnumbered, representing a family's entire future, and he begins his defense by reminding the judge of the judge's own prior oath.
It is the opening move of the speech that will break Joseph's disguise.