Romans 8:23 meaning

This second mention of adoption again recalls the first of two stages of Roman adoption, being placed as a son at age 14, with voting rights. Every believer will gain a new, resurrected body. Some believers will also receive the reward of the inheritance of sharing Christ's reign, those who suffer with Him (Romans 8:17b).

Paul is telling his audience, the believers in Rome at the time, that we (believers) also groan and eagerly wait for the redemption of our bodies in a similar way that creation does. That longing is within us if we listen to the Spirit. The Holy Spirit is given to believers once they believe on Jesus (Ephesians 1:3): And not only this, but also we ourselves, having the first fruits of the Spirit (v 23). 

The this in the phrase And not only this, refers to the creation groaning as it eagerly awaits the restoration of faithful and righteous humans reigning over it in harmony with God and one another. Paul desires the disciples in Rome to gladly endure the sufferings of Christ, even as he endures, that they might become "fellow heirs with Christ" in reigning over the earth (Romans 8:17b). Paul here asserts that the benefit of believing in Jesus is not just a future reward, there is also a current benefit, that we have been gifted the first fruits of the Spirit. 

The Holy Spirit is our first fruits, the first tangible benefit resulting from putting our faith in Christ. The Spirit is our helper, giving us the power to overcome temptation, and help us avoid the negative consequences of sin. Yet, even as believers who have the Holy Spirit, we ourselves groan within ourselves, waiting eagerly for our adoption as sons, the redemption of our body (v 23). We have this great benefit of the Spirit, but we know that things are just not right. We long for all that is broken in the world to be restored. 

This restoration includes the redemption of our body. This refers to a time when God gives us new, resurrected bodies. Even with the Spirit and the hope we have in Christ, we are still trapped with our old, sinful, mortal flesh for the time being. We desire to one day be fully restored to God's design, where we will be free from sin and pain, and live in perfect harmony with each other and God. 

This could be part of what Paul is referring to when he says our adoption as sons, when we become heirs of God as we enter into His presence and are given new bodies. As believers, we are children of God, and unconditionally are also heirs of God and will receive new bodies (1 Corinthians 15:17, 20).

Every believer has been saved from Hell to Heaven and will receive a new body which has no sin nature. And some believers will also receive additional rewards, as we saw in verse 17b, the greatest of which appears to be to share in Christ's inheritance.