This certainly is an argument used by OSAS advocates. They don’t believe that once a person is saved that he cannot be unborn again when he sins.
The problem with this is that the argument is based on natural fact and then applied to the spiritual. Their mistake is to argue from the natural to the spiritual just to defend a teaching that is not Biblical. They base things on human reasoning from nature. For instance, they say a saved person (a sheep) cannot become a goat (lost). Yet they have no problem believing a goat can become a sheep!
Before we were saved, we were lost in the sins we have committed. All of us were without Christ, having no hope (Eph. 2:12). All sinners are “children of the devil” and “sons of the evil one” (Acts 13:10; 1 John 3:10; Matt. 13:38). In our lost state, the devil was our spiritual father (John 8:44). Our relationship changed at the point of repentance and faith towards our Lord Jesus. God became our Father and we became the children of God.
It doesn’t take much to switch back to having the devil as our spiritual father once again. One does not have to be “unborn” to do this. The person simply ceases to abide in Christ. He doesn’t become “unborn,” he simply “dies.” The opposite of birth is death. Just like Adam and Eve, one can die spiritually (Luke 15:24,32; Rom. 8:13; James 1:14,15; etc.). It is possible to stop believing (Luke 8:13), have our faith destroyed (2 Tim. 2:18), and for our faith to become shipwrecked (1 Tim. 1:19,20)
Being born again has nothing to do with our bodies changing physically. Our nature does not change. Being born again means a “moral change”.
Jesus told Nicodemus about being “born again,” but Nicodemus did not understand. Nicodemus was looking at the physical aspect of what Jesus was saying. He says, “How can a man be born when he is old? Can he enter the second time into his mother’s womb, and be born?” Jesus responded, “Are you the teacher of Israel and do not know these things?”
Nicodemus was a teacher of Israel and did not know these things when he should have. The Old Testament speaks of a God giving us a new heart (Psa_51:16-17; Eze_11:19; Eze_36:26.) But this new heart is not given until we repent of our sins; until there is a moral change. (See “When Does The Sin Stop)
Let the wicked forsake his way, And the unrighteous man his thoughts; Let him return to the LORD, And He will have mercy on him; And to our God, For He will abundantly pardon. (Isa. 55:7)
“ For godly sorrow produces repentance leading to salvation, not to be regretted; but the sorrow of the world produces death. For observe this very thing, that you sorrowed in a godly manner: What diligence it produced in you, what clearing of yourselves, what indignation, what fear, what vehement desire, what zeal, what vindication! In all things you proved yourselves to be clear in this matter.” (2 Cor. 7:10-11)
“For the grace of God that brings salvation has appeared to all men, teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly in the present age, looking for the blessed hope and glorious appearing of our great God and Savior Jesus Christ, who gave Himself for us, that He might redeem us from every lawless deed and purify for Himself His own special people, zealous for good works. (Titus 2:11-14)
Do not be like Nicodemus and fail to realize that the new birth is a “moral change,” not a physical or metaphysical change.