John 8:39 - Matthew Poole's English Annotations on the Holy Bible

Abraham is our Father; this was their continual boast, as may be learned from Matthew 3:9; glorying in their birth privilege, Abraham being the father of the whole Jewish nation; and in their church privilege, Abraham being the head of the Jewish church, and he to whom the promises were made. But Christ taketh them off this glorying, by reminding them, that the blood of Abraham running in their veins would be of little significance to them, so long as they did not walk in Abraham's steps. Men are truly to be accounted the children of those, not from whom they are naturally descended, but whose steps they walk in, and whom they imitate in their conversations.