The paramount issue here is that Salvation is a gift and received by faith alone. It is by grace and nothing that man does. Salvation is not by faith and some ceremony such as baptism. Once a man receives Jesus Christ as personal Lord and Savior, that person is born of God! Having being born, you cannot be unborn. When regeneration is ordained the Christians life is forever changed.
Romans 6: 22-23
22 But now that you have been set free from sin and have become slaves of God, the fruit you get leads to sanctification and its end, eternal life. 23 For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord.
The believer’s life is eternal!
John 1: 9-13
9 The true light, which gives light to everyone, was coming into the world. 10 He was in the world, and the world was made through him, yet the world did not know him. 11 He came to his own, and his own people did not receive him. 12 But to all who did receive him, who believed in his name, he gave the right to become children of God, 13 who were born, not of blood nor of the will of the flesh nor of the will of man, but of God.