Genesis 22:20-24 NIV
20Some time later Abraham was told, “Milcah is also a mother; she has borne sons to your brother Nahor: 21Uz the firstborn, Buz his brother, Kemuel (the father of Aram), 22Kesed, Hazo, Pildash, Jidlaph and Bethuel.” 23Bethuel became the father of Rebekah. Milcah bore these eight sons to Abraham’s brother Nahor. 24His concubine, whose name was Reumah, also had sons: Tebah, Gaham, Tahash and Maacah.
This short history seems to be introduced solely for the purpose of preparing the reader for the transactions related Genesis 24(Isaac and Rebekah), and to show that the providence of God was preparing, in one of the branches of the family of Abraham, a suitable spouse for his son Isaac.
Refer to the following diagram for your better understanding.