Paul uses the picture of adoption five times in his writings. Once describing Israel’s adoption by God (Romans 9:4), and four times describing the adoption of Gentiles into his family (Romans 8:15, 23; Galatians 4:5; Ephesians 1:5).
But what does Paul mean when he refers to being adopted by God? The answer to that is more involved than we might think based on present-day adoption practices.
Adoption in the Roman World
Adoption today generally deals with infants or young children, usually because of the inability to have children or to provide a home for children who would otherwise not have a loving family. But adoption was quite different in the Roman world of the first century.
In that time and place, adoption was primarily about securing an heir. Among the Roman aristocracy, families were generally small, child mortality was high, and failing to have a son who could inherit the estate was not uncommon.
Adoption provided a means to be able to carry on the family name and estate when a natural son was not available.
There are some aspects of Roman adoption that are especially relevant to Paul’s usage of adoption. First, as mentioned above, adoption was concerned with inheritance. The reason for being adopted was to provide an heir when one was not otherwise available.
Only free Roman citizens could be legally adopted. Non-citizens and slaves could not be adopted. However, a slave could be freed, and then as a freedman, he could be adopted.
If the slave were owned by someone other than the one freeing him, he would first need to be purchased. And once the purchase price was paid, the slave could be freed.
When a person was adopted, they were given a new name, the name of the family they were adopted into. If the one being adopted was not previously the head of his family, he brought nothing with him into the adopted family.
However, if he was the head of his original family, all he had come with him was placed under the ownership of his new father. So, adoption essentially resulted in a new start in life.
Slaves to Sin
Paul’s use of adoption is not the straightforward adoption of one Roman citizen by another. Instead, he focuses on the adoption of one who was a slave and who must first be redeemed and set free from slavery before adoption.
Several times in Paul’s letter to the Roman church, he refers to us as having been slaves to sin (Romans 6:6,16,17,20; 7:14, 25) or that sin was our master (Romans 6:14).
Sin is not used here in the sense of individual acts of disobedience. Rather, sin personifies our fallen human nature.
We were not free to choose our own future. We were slaves and had no prospects of escaping that slavery. While we had limited freedom to order our lives, in the end, we were still slaves to sin, owned and controlled by that nature.
Redeemed and Set Free
Romans 6:17-18, while affirming that we were slaves to sin, says that we have now been set free from that slavery to sin.
And, in Revelation 5:9, the heavenly host sang of Jesus, “You are worthy to take the scroll and to open its seals, because you were slain, and with your blood you purchased for God persons from every tribe and language and people and nation.”
God did for us what we were unable to do for ourselves. He paid the price for our freedom to our former master. And he set us free.
Adopted into God’s Family
As mentioned in the opening, Paul uses the expression “adoption to sonship” five times in his writing. We were not initially born into God’s family as sons and daughters. We were slaves to another master. But God, who purchased our freedom, adopted us into his family.
No longer are we on the outside looking in. We are now intimate members of God’s family. In Romans 8:15, Paul said that “the Spirit you received brought about your adoption to sonship. And by him, we cry, ‘Abba, Father’.”
Abba is an Aramaic word for father. According to Vines Expository Dictionary, this is the word a young child would use for their father, making it equivalent to our “daddy.”
Not only are we children of God now. But we are called “dearly loved children” in Ephesians 5:1. And 1 John 3:1 refers to the “great love the Father has lavished on us, that we should be called children of God!”
While God’s love extends to the whole world (John 3:16), it is especially given to those who are now members of his family, his dearly loved children.
Heirs of God
In the Roman world, adoption was primarily for the purpose of inheritance. And that is no different in the adoption into the family of God we have experienced. Romans 8:17 tells us that “if we are children, then we are heirs — heirs of God and co-heirs with Christ.”
But this adoption as heirs is different from the Roman adoption of an heir. In the Roman world, inheritance did not occur until the death of the one owning the estate that would be inherited. But we are God’s heirs without his death.
This inheritance is currently something we look forward to. In Ephesians 1:14, Paul tells us that the Holy Spirit living in us is “a deposit guaranteeing our inheritance until the redemption of those who are God’s possession.”
Our inheritance awaits not God’s death but ours. Today we experience but a taste of what awaits us. But once our redemption is complete, we will fully experience the inheritance prepared for us.
The thought of being a co-heir, or joint heir, with Christ, seems a bit strange at first. Surely our place in the eternal kingdom is not the same as that of Jesus, which is what joint inheritance would imply.
But, as believers, we are in Christ. And, in Christ, his experience becomes ours. We share in his life now. And we will through eternity. It is as we are in Christ, then, that we can be joint heirs with him.
Bringing it All Together
Paul’s use of adoption imagery is most evident in Galatians 4:4-7.
But when the set time had fully come, God sent his Son, born of a woman, born under the law, to redeem those under the law, that we might receive adoption to sonship.
Because you are his sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, “Abba, Father.” So, you are no longer a slave but God’s child; and since you are his child, God has made you also an heir.
This passage begins with our redemption from the slave market, leading to our adoption, becoming loved members of his family, and concluding with being made God’s heirs.