The Gospel is the simple message of new life in Jesus Christ. It is the "Good News" of what God did for all people by the Cross and resurrection of His Son. Religion focuses on what we must do to please to God. The Gospel is just the opposite; it is about what God did for us through Christ Jesus.
(Note: In this article, God, Jesus or the Holy Spirit living in you all mean the same thing and are used interchangeably. Also, nature, spirit, and heart all mean the same thing and they are used interchangeably as well. For shorter answers to the issues discussed in this article, click here.)
New Life in Jesus Christ
When you place your trust in Jesus Christ as Savior, God literally removes your old sinful inner nature and replaces it with a brand new, clean heart (Ezekiel 36:26; Romans 6:6). Since your new inner spirit is completely clean and without sin, God now has a suitable place within you where He can live. God joins His righteous and eternal life to your new born again heart.
Because of this, you have become a completely new person on the inside (2 Corinthians 5:17); the old inner you is gone, dead and buried forever. You are now and forever free from sin in your born again heart (Romans 6:7,18,22). In fact, you can never sin in your inner spirit because Jesus in you can never sin (1 John 3:9).
But there is a problem: you still "live" in the same mortal body as you did before you became a believer. Thankfully God has a solution for this. A helpful way to understand yourself is that you are a redeemed and righteous spiritual person living inside an "earth suit" (or earthly "tent") which has not yet been redeemed or made righteous (2 Corinthians 5:4).
("Earth suit" coined by Bill Gillham)
Righteous Children of God
As a believer in Jesus Christ, you are righteous. Righteousness is not merely "imputed" or credited to you as is commonly taught; this is one of the worst lies that religion teaches. God gives you righteousness as a gift, and the gift is Jesus Christ living in you (Romans 5:17b). As Jesus joins inseparably and eternally as one to your born again heart (1 Corinthians 6:17), you are in Him and He is in you (John 14:20).
Although it disturbs some when you declare that believers are just as righteous as Jesus Himself, it is true. Think about it. If Christ is joined as one to you in a bond that can never be broken, He has given His life to you. You are what He is - righteous. You do not become divine, but you do get to share in the life of the Creator (2 Peter 1:4).
This is critical to understand because your new inner spirit is the real you, not your flawed outer mortal body. Your mortal body is your temporary "house" (2 Corinthians 5:2; 4:16) which will be replaced one day with an immortal body (1 Corinthians 15:53). This is what grace and the New Covenant are all about, God welcoming people into His kingdom, already prepared to stand in His presence. All of this is made possible by the Cross and resurrection of Jesus Christ.
Since your mortal flesh has not yet been redeemed, it has no capacity to be righteous like your new inner spirit. The Apostle Paul even says that your flesh can make you "groan" (2 Corinthians 5:4; Romans 8:23). This is the reason you live by faith. Faith is following Christ's indwelling life instead of you living by your own human effort.
As you walk with Jesus, sin fades into the background; Christ is living His righteous life in you and through you, even when you are not consciously aware of it. If you do stumble, simply return to walking with Christ in faith. You do not have to do anything to get back into fellowship with God. You can never get out of fellowship with God because He has permanently joined His life to your life. God never condemns His children (Romans 8:1); He may guide you in a new, better direction, but He never condemns you.
Therefore, in spite of your mortal flesh, your inner spirit is redeemed and sealed by God's Spirit (2 Corinthians 1:22; Ephesians 1:13). You are forever acceptable to God because He put His very life into your born again heart. This is what makes you righteous, worthy of God's kingdom (Colossians 1:22).