The family freedom (Rom. 8:12–18). This paragraph describes a special relationship with the Father called “adoption,” which must not be confused with adoption in the Western world. In the New Testament, adoption is the act of God whereby he gives each of his children an adult standing in the family the instant he or she is born again. You do not get into God’s family by adoption but by regeneration. Why? Because an adopted child does not have the same nature as his adoptive parents. God’s children have God’s own nature because they have been born of God’s Spirit (2 Pet. 1:4). Adoption has to do with our standing in the family. It simply means that God treats us as adults, not as babes, and gives us adult privileges.
For example, a baby does not even know he is a baby, and he certainly does not know his own parents. Even if a baby did know his own father, he would not be able to speak to him. But God’s children know they are God’s children! They not only know who their Father is, but they are able to speak to him and call him “Abba [Papa], Father!” For the most part, children live in bondage and fear until they are old enough to care for themselves; but God’s children are free from both bondage and fear.
Why does God adopt his children and give them an adult standing in the family? So that they will have the freedom to draw upon all his resources and grow into mature sons and daughters. We are free to walk with him and talk with him, free to hear his Word and follow his Spirit. Even though we constantly need to grow, we do so in a family atmosphere of freedom and grace, not bondage and law.
Wiersbe, Warren W. Be What You Are: 12 Intriguing Pictures of the Christian from the New Testament. Wheaton, IL: Tyndale House, 1988.