Genesis 41 - 42

After 13 years in Egypt, Joseph is promoted from prison to being the Prime Minister in one day, after he interpreted the dreams God gave the king, that predicted 7 years of incredible bounty, and then 7 years of extreme famine.

In the early years of the famine Jacob sends 10 of his sons to buy grain in Egypt, where they unknowingly meet up with Joseph. Joseph gives them grain, but keeps Simeon as hostage against their returning with Benjamin, when they come to buy grain again.