When you are saved, you are born again. This is the doctrine of regeneration.

Titus 3:5Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;
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Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost;

Notice that you are saved by the washing of regeneration. The word “regeneration” means to be reborn. You are said to be born again because your salvation is your second birth.

Read the teaching of John 1:12-13 [12] But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name: [13] Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.
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But as many as received him, to them gave he power to become the sons of God, even to them that believe on his name:  Which were born, not of blood, nor of the will of the flesh, nor of the will of man, but of God.

While your first birth was physical, your second birth is spiritual (“of God”). By this new birth you become one of the sons or children of God.

Since you have been born into the family of God, you cannot become lost by denying your birth. A child naturally born cannot cease to be the father’s child, no matter what is said or what separations are made. So, an individual born into the family of God cannot simply cease to be the Father’s child. In order to lose your salvation, you must somehow unbirth yourself from the family of God. That is step eight.