Sons and heirs
To be sure, Paul touches on the obligation Christians have to curb the “misdeeds of the body.” But this is not viewed as a burdensome thing, something we now have to do. Rather, Paul hurries on to provide the proper gospel motivation and the right reason for doing so.
For you did not receive a spirit that makes you a slave again to fear, but you received the Spirit of sonship. And by him we cry, “Abba, Father.” 16 The Spirit himself testifies with our spirit that we are God’s children. 17 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.
The four instances of pneuma in these verses again present us with an interesting mix of uppercase and lowercase uses. When Paul says in verse 14 that “those who are led by the Spirit of God are sons of God,” pneuma unquestionably calls for a capital S. In the next verse, however, it seems more likely that Paul intends both instances of pneuma to be the lowercase usage. Literally, the apostle writes, “You did not receive a [pneuma] of slavery again to fear, but you received a [pneuma] of adoption as sons.” The two uses are on the same level; both should be translated with a lowercase s, “spirit.”
Note first of all what Paul here rules out with the words, “You did not receive a spirit that makes you a slave again to fear.” The majority of the Roman Christians were of a gentile, pagan background. Paul is taking them back to those miserable days when they had worshiped false gods before coming to know Christ. They had felt obligated to try and earn favor from harsh and demanding gods by bringing the right offerings and living the right kind of lives. When they had failed, they feared the wrath of the offended deities.
With the work of the Holy Spirit in their hearts, all of that had become a thing of the past. They now know a gracious God who has done everything for them and who has given them everything as a gift through Christ.
Now they have the heart and mind not of a slave, but of a son. Paul tells them, “You received the [s]pirit of sonship. And by [it] we cry ‘Abba, Father.’” Abba is simply the Aramaic word for “father.” It is the type of address a child would use to go up to a parent and ask for something. Children don’t stop and wonder whether this would be a convenient time to interrupt what their parents are doing. No, they confidently ask for whatever they need whenever they want it. That is the kind of confidence the Holy Spirit instills in believers, so that they approach God “as boldly and confidently as dear children ask their dear father,” to use Luther’s comparison (The Lord’s Prayer, “The Address”).
How do believers know they may do this? The apostle answers, “The Spirit himself testifies with our spirit that we are God’s children.” Such confidence isn’t arrogance or presumption. It is permissible and proper because we’re children and God is our heavenly Father. Through the means of grace, through Word and sacrament, the Holy Spirit works in our hearts, in our “spirit,” the conviction and the assurance that we are children of God (see 1 John 4:13).
Being children of God, who are permitted to call God our Father, has some absolutely mind-boggling implications. If we are “God’s children,” then the Son of God is our brother by virtue of having the same Father, and what’s more, we are in line for all the blessings the Father accords to his Son. Paul attempts to give us a hint of what that means when he says, “Now if we are children, then we are heirs—heirs of God and co-heirs with Christ.”
Everything the risen, triumphant, ascended Christ has received from his Father belongs also to us. Everything serves his church, and it therefore protects and sustains us even now. But the full realization of that will come only in heaven—only after the trials and tribulations of this world are permanently replaced with the glories of heaven. Then we will see with our eyes the inheritance we now have by faith. Hence Paul can say that we are “heirs of God and coheirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory.”
Again we have a conditional sentence, but the Greek construction makes plain that the matters under discussion are not in doubt. Our inheritance is a sure thing—as is the certainty that we also will have to suffer if we follow the Spirit’s lead in a sinful and perverse world. And yet, the inevitability of suffering is not a cause for concern. The sufferings of this present life are no match for the glorious future that awaits all believers in Christ.