Romans 8:23
The apostle uses the word "firstfruits" in relation to redemption, and he employs "Spirit" in the same general sense as "guarantee" of the Spirit as in
Ephesians 1:14.
Firstfruits here literally means "a beginning," indicating a start has been made and more will follow.
John W. Ritenbaugh
Our Uniqueness and Time
(excerpt)
The picture Paul paints here ties together several things he has written in Romans 8 so far. He has said that God has given us in the Holy Spirit what he called the
"Spirit of adoption" (Romans 8:15). We have already been adopted and have become the full children of God through faith in Christ. So what are we waiting for if the adoption is complete?
Paul has written about a disconnect between our spirits and our bodies: "…although the body is dead because of sin, the Spirit is life because of righteousness" (Romans 8:10).
It's true that we are fully God's children right now through faith in Christ, but we have yet to meet our Father in person. We have been freed from the eternal penalty for sin, but our bodies continue to experience the temporary consequence of sin: death. We are dying, and these bodies will die.
So what are we adopted children of God waiting for? We're waiting for our bodies to be redeemed after we die physically and are then resurrected as Christ was. Or as someone put it: Our adoption is complete; we're just waiting for our father to come and pick us up so that we can be with Him.
(here)
What does Romans 8:23 mean? - Online Bible Commentary
the argument seems to be unnecessary since both have relevance