No if someone chooses to go back to their old life and ways, they were never Christians to begin with. A “Christian” is not someone who has ‘made a profession’ by saying a prayer, or signing a card, or coming forward at the end of a church service. Neither is a Christian defined as someone born into a Christian family. A Christian, according to the Bible, is a person who has, by faith, received and fully trusted in Jesus Christ as the only Savior from sin (John 3:16; Acts 16:31; Ephesians 2:8-9) and became a new creature in Christ Jesus. The new creation is described in 2 Corinthians 5:17: “Therefore, if anyone is in Christ, he is a new creation; the old has gone, the new has come!” The word “therefore” refers us back to verses 14-16 where Paul tells us that all believers have died with Christ and no longer live for themselves. Our lives are no longer worldly; they are now spiritual. Our “death” is that of the old sin nature which was nailed to the cross with Christ. It was buried with Him, and just as He was raised up by the Father, so are we raised up to “walk in newness of life” (Romans 6:4). That new person that was raised up is what Paul refers to in 2 Corinthians 5:17 as the “new creation.”
To understand the new creation, first we must grasp that it is in fact a creation, something created by God. John 1:13 tells us that this new birth was brought about by the will of God. We did not inherit the new nature, nor did we decide to re-create ourselves anew, nor did God simply clean up our old nature; He created something entirely fresh and unique. The new creation is completely new, brought about from nothing, just as the whole universe was created by God ex nihilo, from nothing. Only the Creator could accomplish such a feat.
Second, “old things have passed away.” The “old” refers to everything that is part of our old nature—natural pride, love of sin, reliance on works, and our former opinions, habits and passions. Most significantly, what we loved has passed away, especially the supreme love of self and with it self-righteousness, self-promotion, and self-justification. The new creature looks outwardly toward Christ instead of inwardly toward self. The old things died, nailed to the cross with our sin nature.
Along with the old passing away, “the new has come!” Old, dead things are replaced with new things, full of life and the glory of God. The newborn soul delights in the things of God and abhors the things of the world and the flesh. Our purposes, feelings, desires, and understandings are fresh and different. We see the world differently. The Bible seems to be a new book, and though we may have read it before, there is a beauty about it which we never saw before, and which we wonder at not having perceived. The whole face of nature seems to us to be changed, and we seem to be in a new world. The heavens and the earth are filled with new wonders, and all things seem now to speak forth the praise of God. There are new feelings toward all people—a new kind of love toward family and friends, a new compassion never before felt for enemies, and a new love for all mankind. The things we once loved, we now detest. The sin we once held onto, we now desire to put away forever. We “put off the old man with his deeds” (Galatians 3:10), and put on the “new self, created to be like God in true righteousness and holiness” (Ephesians 4:24).
What about the Christian who continues to sin? There is a difference between continuing to sin and continuing to live in sin. No one reaches sinless perfection in this life, but the redeemed Christian is being sanctified (made holy) day by day, sinning less and hating it more each time he fails. Yes, we still sin, but unwillingly and less and less frequently as we mature. Our new self hates the sin that still has a hold on us. The difference is that the new creation is no longer a slave to sin, as we formerly were. We are now freed from sin and it no longer has power over us (Romans 6:6-7). Now we are empowered by and for righteousness. We now have the choice to “let sin reign” or to count ourselves “dead to sin but alive to God in Christ Jesus” (Romans 6:11-12). Best of all, now we have the power to choose the latter.
The new creation is a wondrous thing, formed in the mind of God and created by His power and for His glory.
God bless you!!! :):)