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

And, predicting that God would consider the Gentiles right with Him by [their] faith, the Scriptures previously recorded [this promise of] the Gospel to Abraham by saying [Gen. 12:3], "All nations will receive a blessing through your descendant [i.e., Jesus]."

For if the inheritance [of never ending life] can be obtained by [obeying the requirements of] the law of Moses, it would not come from the promise [of God]; but God provided [this inheritance] for Abraham according to [His] promise.

What then is [the benefit of] the law of Moses? It was introduced [as part of God's revelation] in order to define what sin was, until the seed [i.e., Jesus] would come, to whom the promise [of never ending life] was made. The law of Moses was ordained through [the medium of] angels and [delivered] through the hand of an intermediary [i.e., Moses].

But the Scriptures indicate that everything [i.e., everyone] is under the control of sin, so that the promise [of never ending life] could be available [only] to those who have faith in Jesus Christ.

Now the son [Ishmael], born to the slave woman, was born simply of their natural relationship; but the son [Isaac], born to the free woman, was born in fulfillment of a [divine] promise.

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