Bereisheet (Genesis): Mikeitz > Ch 42 & Ch 43
Jacob sends his sons down to Egypt, all except for Benjamin (the youngest)
Jacob sent his ten sons to buy grain from Egypt. Jacob didn’t send Joseph’s brother Benjamin because he feared for him.
Joseph hides his identity from his brothers and demands that they bring Benjamin to Egypt
Joseph's brothers prostrated themselves to Joseph, with their faces to the ground. Joseph recognized them but they didn’t recognize him and they talked through an interpreter. Joseph accused them of being spies and challenged them to prove otherwise. They said that they have another brother back home. So, Joseph imprisoned Simeon and sent others back home with loads of grain and without taking any money. Simeon would be released only when they would bring Benjamin to Egypt. Joseph’s brothers talked between themselves saying that this trouble came to them because they killed Joseph. Joseph turned away from them and wept.
Joseph’s brothers returned to their father and told him of what has happened. Joseph’s brothers and their father became frightened. And Jacob did not want to send Benjamin with his brothers even as Reuben promised to take responsibility for him.
for the interpreter was between them
For whenever they spoke with him, the interpreter, who knew both Hebrew and Egyptian, was between them, and he would interpret their words for Joseph and Joseph’s words for them. Therefore, they thought that Joseph did not understand Hebrew. — [from Targum Onkelos]
Jacob sends his sons down to Egypt again, this time with Benjamin
When all grain brought from Egypt ended, Jacob sent his sons to Egypt again. He allowed them to take Benjamin, and Judah promised to take responsibility for what happens to him.
Upon seeing Benjamin, Joseph wept privately. Joseph had dinner with all of his brothers and hid his identity from them again. He gave Benjamin 5 times more food than to anyone else.