There is an idea held by some, and rooted in ancient gnosticism, that our fleshly bodies do not receive the same salvation as do our spirits. Some go so far as to say that the spirit of man is saved immediately, perfectly, and irrevocably, by faith alone, but the fleshly body must be saved by works over time.
Those who hold this doctrine are mistaken about three important issues concerning the fleshly body of the Christian: its future redemption, its present sanctification, and its past death to sin.
The Christian’s physical body is presently in a humble and mortal state, waiting to be glorified as Christ's physical body has been glorified (Philippians 3:20-21).
The Christian’s natural body is destined to be resurrected as a spiritual and immortal body fit for eternity (1Corinthians 15:35-58).
Paul refers to the resurrection of the body as the "redemption of our body" (Romans 8:23-24).
This awaited redemption of the body is not a redemption with regard to sin, but a redemption with regard to the humble, physical, mortal and corruptible state in which the body is subject to physical death.
Our bodies are not in an unsaved, sin-tainted state, unredeemed with regard to sin. We have redemption in the form of forgiveness of sin as a completed work of Christ (Ephesians 1:7).
As yet, however, we do not have redemption in the form of glorious immortality in heaven, although we do have the immutable pledge and seal of that inheritance (Ephesians 1:13-14).
"Now may the God of peace Himself sanctify you entirely; and may your spirit and soul and body be preserved complete, without blame at the coming of our Lord Jesus Christ." (1Thess 5:23).
In that verse whatever is said of the spirit, is also said of the soul and body. There is entire sanctification of spirit, soul, and body, and this whole person is preserved so as to be found blameless at the second coming of Christ.
Paul says, "I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your reasonable service" (Romans 12:1).
We all know that a sacrifice, to be acceptable and well-pleasing to God, must be spotless and without blemish. If our bodies have not yet been saved and sanctified, along with our spirits, how could we possibly present them to God as a living and holy sacrifice?
Paul says, "Do you not know that your body is a sanctuary of the Holy Spirit who is in you, whom you have from God, and that you are not your own for you have been bought with a price? Therefore glorify God in your body." (1Cor 6:19-20).
If our bodies of flesh are yet unsaved and in any bondage to sin, how could they be fit to serve as a sanctuary of the Holy Spirit?
Paul makes this statement: "Though the body is dead because of sin, yet the spirit is alive because of righteousness" (Romans 8:10).
Paul is making the same contrast here as he did in chapter 6 where he wrote...
"If we have died with Christ, we believe we shall also live with him... consider yourselves to be dead to sin, but alive to God in Christ Jesus. Therefore do not let sin reign in your mortal body that you should obey its lusts, and do not go on presenting the members of your body to sin as instruments of unrighteousness, but present yourselves to God as those alive from the dead, and your members as instruments of righteousness to God" (Romans 6:1-23).
In saying, "The body is dead because of sin", Paul does not mean that the Christian’s body is still dead in sin, but rather that it has become dead to sin.
As Peter also says, "Christ himself bore our sins in his body on the cross that we might die to sin and live to righteousness" (1Peter 2:24).
Because of your sins, Jesus gave his body as a sacrifice whereby your body is made dead to sin. "Those who belong to Christ Jesus have crucified the flesh with its passions and desires" (Galatians 5:24).
That is the sense in which "the body is dead because of sin, yet the spirit is alive because of righteousness" (Romans 8:10). Your forgiven spirit is free to walk in newness of life, using your body as an instrument of righteousness.
If our bodies share in the sufferings that Christ endured in his body, surely our bodies also share in the salvation which his suffering brought about (1Peter 4:13).