9 You, however, are not in the flesh but in the Spirit, if in fact the Spirit of God dwells in you. Anyone who does not have the Spirit of Christ does not belong to him.
10 But if Christ is in you, although the body is dead because of sin, the Spirit is life because of righteousness.
11 If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ Jesus from the dead will also give life to your mortal bodies through his Spirit who dwells in you. – Romans 8:9-11
Paul tells the people in the church at Rome that they are “in the Spirit”. They have obeyed Christ and walk now not according to the flesh but according to the Spirit. The truth is if you do not have the Holy Spirit you do not belong to God. The Holy Spirit is the seal of God in our hearts that proves our redemption:
And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. – Ephesians 4:30
We live in a strange age where two kingdoms are running on the earth. Jesus has come and through His victory over Satan, sin and death at the cross has brought the Kingdom of God to mankind which you can enter by faith in Him. But the kingdom of this world, ruled by the evil one, is still very much in existence. We are dwelling in our bodies which Paul compare to living in tents (2 Corinthians 5:4). We are in an army that is in enemy territory. Therefore, we should not get entangled in the cares of this world as that stops us from being the spiritual army God wants to rescue people from the enemy’s control. We dwell in a body that is destined for death and still has a sin nature. But, when we die Jesus has promised we will be raised again with Him.
7 For one who has died has been set free from sin.
8 Now if we have died with Christ, we believe that we will also live with him.
9 We know that Christ, being raised from the dead, will never die again; death no longer has dominion over him. – Romans 6:7-9
So we live in the spiritual war zone between the flesh and the Spirit. But the Spirit gives us life. We should live in the Spirit following the lead of out Lord. Verse 11 clearly gives us the promise that we will be resurrected as Jesus was. We who believe (in Jesus, that He is the Son of God, that He was raised from the dead and that He is our Lord), we are in the Spirit and have the promise of eternal life, being with God for ever.