It happened, while Yisra'el lived in that land, that Re'uven went and lay with Bilhah, his father's concubine, and Yisra'el heard of it. Now the sons of Ya`akov were twelve.
This is the history of the generations of Ya`akov. Yosef, being seventeen years old, was feeding the flock with his brothers. He was a boy with the sons of Bilhah and Zilpah, his father's wives. Yosef brought an evil report of them to their father.