Joseph's brothers hated him because their father favored him. In fact, Joseph's father loved him so much that he had a coat of many colors custom tailored made just for him. The brothers were so angry and jealous
Genesis 39:1-6 (KJV)
1 And Joseph was brought down to Egypt; and Potiphar, an officer of Pharaoh, captain of the guard, an Egyptian, bought him of the hands of the Ishmeelites, which had brought him down thither.
2 And the LORD was with Joseph, and he was a prosperous man; and he was in the