To answer your good question, let’s read Romans 8:9-10, “But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness.”

Speaking to believers, the Apostle Paul assures us that we have the Spirit of God dwelling inside us, and so we do not live in the flesh, rather we live according to the Spirit.  We read of all true believers in 1 Corinthians 6:19, “What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?”

Now, if Christ is in us, the body is dead because of, or by reason of, sin.  Although we may have eternal life, we still live in bodies that are subject to death, and we will die one day unless the Lord returns before we die.  However, by the Spirit of God we have been made partakers of the risen life of Christ.  We read in Ephesians 2:5-6, “Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;) And hath raised us up together, and made us sit together in heavenly places in Christ Jesus.”  Because Christ lives, we live!  2 Corinthians 5:21 tells us, “For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.”  Is that too hard to comprehend?  It is amazing!  We have been made the righteousness of God in Christ Jesus!  Today!  Right now!  If you have put your faith in the Lord Jesus Christ, you are the living righteousness of God.

Now let’s read Romans 8:11, “But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you.”  Even though the ‘body is dead because of sin’, that Holy Spirit of God who raised Christ from the dead (the Spirit that indwells every believer), will also quicken, or raise, our mortal bodies.  This is when our salvation will be fully realized.  Verse 33 of our chapter reads, “And not only they, but ourselves also, which have the firstfruits of the Spirit, even we ourselves groan within ourselves, waiting for the adoption, to wit, THE REDEMPTION OF OUR BODY.”  Thank God, we have been redeemed.  Yet the ‘redemption of our body’ is yet to take place.  That will happen when the Lord returns in the clouds for His church.  Let’s read of that event in 1 Corinthians 15:51-55, “Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed, In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed. For this corruptible must put on incorruption, and this mortal must put on immortality. So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory. O death, where is thy sting? O grave, where is thy victory?”  Oh, glorious day when our bodies are changed, made immortal and incorruptible, and the Lord shall gather us into Himself.  “Even so, come, Lord Jesus.” (Revelation 22:20)

In these 3 verses, we have read about ‘the Spirit’, ‘the Spirit of God’, ‘the Spirit of Christ’, and ‘his Spirit’.  What are we to think of this?  How many spirits are there?  Ephesians 4:4 speaks clearly, declaring that there is “one Spirit.”  So, whether He is called the Spirit of God, the Spirit of Christ, the Holy Spirit, the Holy Ghost, or the Spirit, all refer to that important and vital part of the Godhead…the Holy Spirit.  (204.8)