John Gill Commentary Genesis 22:23

"And Bethuel begat Rebekah. These eight did Milcah bear to Nahor, Abraham`s brother." — Genesis 22:23 (ASV)

And Bethuel begat Rebekah Who was to be and was the wife of Isaac; and, for the sake of her genealogy, the above account is given, as Aben Ezra observes, and so Jarchi; and this is observed to pave the way for the history of the chapter; for no notice is taken of any other of Bethuel's children but her, not even of Laban her brother:

these eight Milcah did bear, to Nahor, Abraham's brother ; this is observed, and the exact number given, as well as their names, to distinguish them from other children of Nahor he had by another woman, as follows: