<p>9:8 <em>That is: it is not the children of the flesh that are children of God, but the children of the promise who are counted as the seed</em>- See on :7. Fleshly descent from Abraham did not make one a member of the seed of promise. That seed was one person- the Lord Jesus. And only identity with Him makes a person part of the promised seed. This connects with all Paul has written in chapters 1-8; that acceptability with God is on the basis of being in Christ and being thereby counted as Christ, who alone is the promised seed. Galatians 3 makes these points again in very clear language.</p>