The first son of Leah with Jacob, the son of Isaac. Reuben and his five brothers (Simeon, Levi, Judah, Issachar, and Zebulun) made up half of the original tribes of Israel. As a boy, Reuben resents that his mother is overpowered by his aunt Rachel. He is the one who brings the mandrakes, plant used to make a woman more fertile, which Leah uses to negotiate with Rachel. Reuben loses the birthright when he lies with Bilah, the concubine of his father, Rachel’s maid. He does it out of pure carnal desire, without much involvement with it. At the end of Jacob’s life, he describes the son as his strength, the principle of his vigor, the most excellent in highness and the most excellent in power and impetuous as water, but when he slept with his concubine he became defiled and lost his rights.