Now, brothers, you [Christians] are children of the promise [made to Abraham. See 3:29] just like Isaac, [Abraham's son] was.

And if you belong to Christ, then you are [truly] Abraham's seed [i.e., his spiritual descendants] and thereby [you will] inherit what was promised to him [i.e., God's blessings].

For it is written in the law about Abraham's two sons [Gen. 16]; one [was] by his slave woman [Hagar] and the other by the free woman, [his wife, Sarah].

[An example of this is] Abraham, who believed God's [promise] and [because of such faith] he was considered right with God.