Therefore you are no longer a slave, but a son; and if a son, then an heir through God. Galations 4:7
Adoption (huiothesia) is a term that the apostle Paul uses several times in his letters. The Greco-Roman concept of adoption is different than the English concept. In English adoption is an action. For example a father “adopts” a son. The Greco-Roman concept of adoption refers to something that sons receive. Sons are not adopted, rather, sons receive the adoption (Gal 4:1-7). This conceptual difference of what adoption is can contribute to a misunderstanding of certain Biblical passages. In the context of the Arminian / Calvinist debate, the meaning of adoption directly relates to our interpretation of Ephesians 1.
In English we associate adoption with parents taking a baby into their family. The baby is “adopted”. He is an outsider prior to adoption, and a son after adoption. However, Huiothesia refers to the standing of someone who is ALREADY a son. Adoption is the right of a son. Adoption is the “inheritance”, “promise”, or “reward” that the son receives as an heir. A father makes promises to his children. These promises are the adoption. Huiothesia is not synonymous with salvation (entrance into the family). Rather, it is the promise of God received by those who are believers in Christ Jesus (Gal 3:22-27).
The reward of the adoption occurs now and after death. This can be seen in Romans 8 (bold mine):
For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons by which we cry out, “Abba! Father!” -Rom 8:15 (NASB)
And not only this, but also we ourselves, having the first fruits of the Spirit, even we ourselves groan within ourselves, waiting eagerly for our adoption as sons, the redemption of our body. -Rom 8:23 (NASB)
Observe in Romans 8:23 that Paul speaks of believers who wait for their adoption. There is a distinction between believing and the adoption. Conversely, sonship (having the legal rights of a son) doesn’t guarantee that the son will apply and benefit from those rights. This can be seen in Romans 9:1-5 (bold mine)
I am telling the truth in Christ, I am not lying, my conscience testifies with me in the Holy Spirit, that I have great sorrow and unceasing grief in my heart. For I could wish that I myself were accursed, separated from Christ for the sake of my brethren, my kinsmen according to the flesh, who are Israelites, to whom belongs the adoption as sons, and the glory and the covenants and the giving of the Law and the temple service and the promises,whose are the fathers, and from whom is the Christ according to the flesh, who is over all, God blessed forever. Amen. (NASB)
Here Paul refers to the nation of Israel – his brothers. Israel has the rights of the adoption, but is failing to apply and benefit from those rights. Again, we see Paul treat adoption as a position rather than an action.
Now, let’s take a look at Ephesians 1:5-6. It is my contention that understanding the Greek concept of adoption takes away the Calvinistic flavor that is sometimes attributed to the passage (bold mine):
In love He predestined us to adoption as sons through Jesus Christ to Himself, according to the kind intention of His will, to the praise of the glory of His grace, which He freely bestowed on us in the Beloved. (NASB)
This could be accurately translated as follows:
In love He predestined us [believers] to receive an inheritance as sons through Jesus Christ to Himself, according to the kind intention of His will, to the praise of the glory of His grace, which He freely bestowed on us in the Beloved.
In other words, God doesn’t arbitrarily adopt particular humans to join his family. Rather, He promises believers an inheritance as His sons in Christ Jesus.
In conclusion, adoption is a standing that believers have as sons in Christ Jesus. The Pauline concept of adoption is best understood as the position of a believer. It is not an action.