Genesis 42:3-8

So Joseph’s ten half brothers went down to buy grain in Egypt, but Jacob did not send Joseph’s full brother Benjamin with them, because he feared something might happen to him. So Israel’s sons were among those who went to Egypt to buy grain, for the famine in the land of Canaan was severe. Now Joseph was the governor of the land of Egypt, which meant he supervised the sale of grain to all the people. One day, Joseph’s ten brothers came and bowed down before him with their faces on the ground. As soon as Joseph saw them, he realized that they were his brothers! But he pretended he didn’t know them and spoke to them harshly: “Where do you come from?” “From the land of Canaan,” they answered, “and we’re here to buy food.” Although Joseph recognized his brothers, they had no clue that it was Joseph speaking to them.