Romans 9:7

nor are all the children Abraham’s true descendants; rather “through Isaac will your descendants be counted.” ¹ 

Nor because they are his descendants are they all Abraham’s children. On the contrary, "It is through Isaac that your offspring will be reckoned."

nor are they all children because they are Abraham’s descendants, but: "THROUGH ISAAC YOUR DESCENDANTS WILL BE NAMED."

Just the fact that they are descendants of Abraham doesn’t make them truly Abraham’s children. For the Scriptures say, "Isaac is the son through whom your descendants will be counted," though Abraham had other children, too.

It wasn't Abraham's sperm that gave identity here, but God's [promise]. Remember how it was put: "Your family will be defined by Isaac"?

And they are not all children because they are the seed of Abraham; but, In Isaac will your seed be named.

and not all of Abraham’s children are his true descendants; but "It is through Isaac that descendants shall be named for you."

nor are they all children because they are the seed of Abraham; but, "In Isaac your seed shall be called."

nor are all the children Abraham’s true descendants; rather “through Isaac will your descendants be counted.” ¹ 

¹ tn Grk “be called.” The emphasis here is upon God’s divine sovereignty in choosing Isaac as the child through whom Abraham’s lineage would be counted as opposed to Ishmael.

sn A quotation from Gen 21:12.