Genesis 35:23

35:23 The sons of Leah were Reuben, Jacob’s firstborn, as well as Simeon, Levi, Judah, Issachar, and Zebulun.

Genesis 38:7

38:7 But Er, Judah’s firstborn, was evil in the Lord’s sight, so the Lord killed him.

Genesis 36:15

36:15 These were the chiefs among the descendants of Esau, the sons of Eliphaz, Esau’s firstborn: chief Teman, chief Omar, chief Zepho, chief Kenaz,