Yusuf's Brothers travel to Egypt
Allah tells;
وَجَاء إِخْوَةُ يُوسُفَ فَدَخَلُواْ عَلَيْهِ فَعَرَفَهُمْ وَهُمْ لَهُ مُنكِرُونَ
And Yusuf's brethren came and they entered unto him, and he recognized them, but they recognized him not.
As-Suddi, Muhammad bin Ishaq and several others said that the reason why Yusuf's brothers went to Egypt, is that after Yusuf became minister of Egypt and the seven years of abundance passed, then came the seven years of drought that struck all areas of Egypt. The drought also reached the area of Kana`an (Canaan), where Prophet Yaqub, peace be upon him, and his children resided.
Prophet Yusuf efficiently guarded the people's harvest and collected it, and what he collected became a great fortune for the people. This also permitted Yusuf to give gifts to the people who sought his aid from various areas who came to buy food and provisions for their families. Yusuf would not give a family man more than whatever a camel could carry, as annual provisions for them.
Yusuf himself did not fill his stomach from this food, nor did the king and his aids eat except one meal a day. By doing so, the people could sustain themselves with what they had for the remainder of the seven years. Indeed, Yusuf was a mercy from Allah sent to the people of Egypt.
Yusuf's brothers were among those who came to Egypt to buy food supplies, by the order of their father. They knew that the Aziz of Egypt was selling food to people who need it for a low price, so they took some merchandise from their land with them to exchange it for food. They were ten, because Yaqub peace be upon him kept his son and Yusuf's brother Binyamin with him. Binyamin was the dearest of his sons to him after Yusuf.
When Prophet Yusuf's brothers entered on him in his court and the center of his authority, he knew them the minute he saw them. However, they did not recognize him because they got rid of him when he was still young, and sold him to a caravan of travelers while unaware of their destination. They could not have imagined that Yusuf would end up being a minister, and this is why they did not recognize him, while he did recognize them.
As-Suddi said that;
Yusuf started talking to his brothers and asked them, "What brought you to my land?"
They said, "O, Aziz, we came to buy provisions."
He asked them, "You might be spies."
They said, "Allah forbids."
He asked them, "Where are you from?"
They said, "From the area of Kana`an, and our father is Allah's Prophet Yaqub."
He asked them, "Does he have other children besides you?"
They said, "Yes, we were twelve brothers. Our youngest died in the desert, and he used to be the dearest to his father. His full brother is alive and his father kept him, so that his closeness compensates him for losing our youngest brother (who died)."
Yusuf ordered that his brothers be honored and allowed to remain