The brothers are unable to speak to Yosef. The Beis HaLevi famously says it was embarrassment -that Yosef called them - specifically Yehuda - on their lie, . "You say you care about your father and little brother," he says to them, "but I am Yosef and I wonder is MY father still alive? Remember what you did to him? Your actions contradict your words."
The Beis HaLevi supports his view with the medrash which seems arbitrary in it’s juxtaposition of Yosef’s question to his brothers and the statement G-d will make to us one day. Just as Yosef states "I am Yosef" and then questions the brothers about how genuine they are in their care, G-d will one day announce to our souls, “I am G-d.” And then he will point out – “maasecha sotrim devarecha, your actions contradict your words.”
Rabbi Bernard Weinberger, author of Shemen HaTov suggests and then proves that it wasn’t embarrassment. The brothers were speechless for another reason. They had never recognized Yosef for who he really was. Long before his beard and position disguised his identity, Yosef was a mystery to his brothers. Rather than trust him at his word, or hope he was something they couldn’t understand they made him into something clear. The brothers decided Yosef was a scoundrel, a threat, a potential murderer, a baby, a daddy’s boy (or worse, depending on who you read and how you think).
Who was Yosef really? Yosef was a tzaddik. He was The Tzaddik. He’s the standard, the bar, the paradigm, the only ancestor that holds the title of Tzaddik as the way that we remember him. The brothers didn’t get it for a long time. When they finally got it, they were speechless. Here was the little twerp and he was ruler of Egypt. And what really got them was that he was righteous, G-d fearing. It was clear. He wasn’t just their father’s favorite or the tattletale they took him for. He was a Tzaddik! Who knew? They thought he was such a nebbish. Now they were speechless.
One day we’ll stand before G-d and He won’t have to point out the contradictions between what we say and what we do. He won’t have to. We’ll see G-d’s glory. We’ll understand and we’ll be speechless.
May we be blessed to get it in regard to each other to the best of our ability as soon as we can.