Tribe of Reuven
Reuven is the firstborn of Jacob, Leah's son. He is mentioned in the Torah as a complex figure. On the one hand, Reuven is described as possessing positive qualities such as responsibility and goodwill, for example when he tries to save Yosef from his brothers. On the other hand, the Torah tells of his sin with Bilha, his father's mistress, an act that caused him to lose the firstborn.