When Joseph revealed his identity to his brothers, he removed all his servants and guards from the room. The Sages disagree whether he acted wisely, and also describe how he convinced his brothers of his true identity.

“And he called: Remove every man from before me” (Genesis 45:1). Rabbi Hama bar Hanina said: Joseph did not act appropriately in removing all of the Egyptians from the room, as had one of the brothers attacked him he would have died. Rabbi Shimon bar Nahman said: He acted properly and appropriately, as he did not shame his brothers before the Egyptians. Joseph knew of his brothers’ righteousness. He said to himself: Heaven forfend, my brothers are not suspected of bloodshed. Joseph strengthened himself and sat before them. He said to them: That brother that you say is dead, are you sure that he is dead? They said to him: Yes. Joseph responded: But why are you lying? Didn’t you sell him? I will summon him and he will answer me. Joseph was calling him: Joseph son of Jacob. The brothers were looking all over the room for him. Joseph said to them: “I am Joseph your brother” (45:4). They did not believe him until he uncovered himself and showed them his circumcision. (Yalkut Shimoni, Vayigash 1:151)