The descendants of Jacob, which later became the nation of Israel, was divided into tribes.
Abraham’s grandson, Jacob (later called Israel) had twelve sons. As the result of deception and competition, they were born to four different women (Jacob’s two wives and their respective maidservants). The descendants of these twelve men would later become known as the twelve tribes of Israel or the nation of Israel.
The sons of Jacob’s first wife, Leah, were Reuben, Simeon, Levi, Judah, Issachar, and Zebulun.
The sons of Jacob’s second wife, Rachel, were Joseph and Benjamin.
The sons of Rachel’s maidservant, Bilhah, were Dan and Naphtali.
The sons of Leah’s maidservant, Zilpah, were Gad and Asher.
Later, when the nation of Israel was divided, the tribes of Judah and Benjamin split off, perpetuating the royal line of king David; they were known as the nation of Judah. This is covered in Second Chronicles as well as First and Second Kings.