Adoption

Therefore, brothers and sisters, we have an obligation—but it is not to the flesh, to live according to it. For if you live according to the flesh, you will die; but if by the Spirit you put to death the misdeeds of the body, you will live.
For those who are led by the Spirit of God are the children of God. The Spirit you received does not make you slaves, so that you live in fear again; rather, the Spirit you received brought about your adoption to sonship. And by him we cry, “Abba, Father.” The Spirit himself testifies with our spirit that we are God’s children. Now if we are children, then we are heirs—heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory. Romans 8:12-17

“Therefore,” because of the position we have as believers (brothers and sisters) in Jesus Christ; because we will never again be under condemnation for our sins; because the Holy Spirit is indwelling us and giving us life, we are obligated; but not to the old sin nature. That person is dead to God. His lusts and human good are of no value to God or to us, so continuing to serve him will neutralize the believer’s life as a child of God. The Holy Spirit will not share your soul with the old sin nature, so one must dominate, the other must diminish. There is a clever little one-liner going around the internet these days: “there are two natures struggling for control within you. The one you feed will grow.” That is absolutely true.

So, let’s give the Spirit of God leadership of our lives. Only the children of God have that privilege. We are not slaves anymore, cowering in fear, but fully inducted sons. Adoption in ancient practice did not mean what it means to us now. If we adopt, it means we take a child born to someone else and make him our own. In ancient Rome, a child born into a family was treated as chattel for the first 14 years. Slaves in the household actually had the rule over him, to see to his upbringing and education. The child wore a robe of a certain design, identifying him as a child. At age 14, the child was adopted in a special ceremony and declared a legal adult, with all the privileges of adulthood. In that ceremony, the father took off the robe of childhood and dressed the brand new adult in the “toga virilis” (robe of manhood). Doncha love it? He could now vote, manage money, get married, and enter military service.

At the moment of salvation, one of the many things the Holy Spirit does for us is He places (adopts) us as adult sons of the Father. Now God is our Daddy. The Holy Spirit knows us as God’s Own children. Since we are without doubt God’s children, we share the sonship and destiny of Jesus Christ.

Now that this faith has come, we are no longer under a guardian. So in Christ Jesus you are all children of God through faith, for all of you who were baptized into Christ have clothed yourselves with Christ. Galatians 3:25-27

Please notice those who are IN CHRIST JESUS are the children of God. Just being born human does not make that so, in spite of what the world wants to think. Those who are not born again by faith in Jesus Christ are worldlings, children of Satan, not children of God.

John 8:43-45 (Jesus speaking to unbelievers) “Why is my language not clear to you? Because you are unable to hear what I say. You belong to your father, the devil, and you want to carry out your father’s desires. He was a murderer from the beginning, not holding to the truth, for there is no truth in him. When he lies, he speaks his native language, for he is a liar and the father of lies. Yet because I tell the truth, you do not believe me!

Romans 8:7-8 The mind governed by the flesh is hostile to God; it does not submit to God’s law, nor can it do so. Those who are in the realm of the flesh cannot please God.

There it is. An unbeliever is not a child of God, does not understand the things of God and is not capable of obeying God’s law. We, the members of God’s Royal Family, are the heirs of salvation and are able to love Him, submit to His authority, grow in grace and knowledge, and please Him by producing the divine good He expects from His sons.

We share in Christ’s sufferings because of the persecution of the world. We will also share in His eternal glory, as God's adult sons.