In today's study, we see that those who are of faith are heirs according to the promise that God gave to Abraham. This is possible because Christ fulfilled the law so that both Jews and Gentiles can now be saved simply by faith. Therefore, being in Christ Jesus, we are spiritually speaking, Abraham's seed according to the promise (not the law).
So, Gentile believers are heirs of the promise that God gave to Abraham, not every promise, but one. Which one? Verse 14 tells us that it is That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith. So, the blessing of Abraham ultimately is the blessing of receiving the promise of the Spirit through faith just as Paul said in 1 Corinthians 12:13, For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
Verses 1-2: Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all; But is under tutors and governors until the time appointed of the father. The heir in this verse speaks of Israel in its infancy as a nation when it was considered to be a child. As such, it was kept under law of the father until the time appointed of the father which to me was the first advent of Christ. It is also referred to as the fulness of time in verse 4.
Paul is using the Roman practice of tutela or guardianship of a minor to make his point. Just as a Roman father would appoint guardians, e.g., tutors and governors, to manage his child's affairs until he came of age, so too, God did for the nation with the Law.
Verse 3: Even so we, when we were children, were in bondage under the elements of the world: Again, the we in this verse is reference to the nation of Israel and not us. He is referring to their bondage under the law, e.g., elements of the world.
Verse 4: But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law, The fullness of time was appointed by the Father when Christ was to come as prophesied in Danial 9:24-27.
Made of a woman speaks of his virgin birth through Mary. It also implies his pre-existence (cf. and John 1:14). And, since Christ was sent to redeem those under the law, he himself had to be born under the law.
Verse 5: To redeem them that were under the law, that we might receive the adoption of sons. Paul here makes an interesting pronoun switch in this verse. He moves from third-person plural (them) to second-person plural (we). That is because the ones who were redeemed were the nation of Israel who were under the law. He also made that clear in chapter 3:13 when he said, Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree: Why? – So that the Galatian gentiles might receive the adoption.
Again, the them is this verse cannot be the Galatian gentiles or the Body of Christ because neither were ever under the law. Israel is the only nation on earth who has ever been under the law, therefore, they are the ones who were redeemed from it. That is the why the kingdom gospel went only to the Jew. They had to be redeemed first from the law and he was their Redeemer. Understand, we Gentiles have never been under the law and therefore were in no need of redemption from it.
It was not until Paul that we hear anything about Jesus being a ransom for all the world as part of the dispensation of grace (1 Timothy 2:1-6). It was only then that salvation could be offered by faith, and faith alone, since the Seed had come and fulfilled the requirements of the law.
Now, by faith, just like Abraham's faith in the promises, we are able to receive the adoption of sons. Another way of expressing it is that after Israel had its chance to be redeemed under the law, then grace could be offered to the Gentiles by faith as revealed in the mystery to Paul.
Now the question arises, has adoption or "sonship" been given to the nation since they rejected the offer? Paul refers to waiting for the adoption in Romans 8:23 when he said, And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, the redemption of our body, but that is referring to the redemption of our bodies someday and is not the same as the adoption or sonship that the nation of Israel enjoys.
Paul also refers to adoption in Romans 9:4 in the present tense when he said, Who are Israelites; to whom pertaineth the adoption, and the glory, and the covenants, and the giving of the law, and the service of God, and the promises; Therefore, we must conclude that adoption and sonship has already been given to the nation even though they rejected the kingdom offer, and to this day, they are being held accountable as the heirs of that kingdom.
That doesn't mean that they are saved, but that they have been redeemed because they price was paid, whether they accepted it or not, and are therefore no longer under the law. That is also why we must conclude that the redemption given to Israel and salvation given to us are not the same thing. The first required nothing on their part, but the second requires faith on our part.