What Does It Mean To Be Born Again?
John 3
1 Now there was a man of the Pharisees named Nicodemus, a member of the Jewish ruling council.
2 He came to Jesus at night and said, "Rabbi, we know you are a teacher who has come from God. For no one could perform the miraculous signs you are doing if God were not with him."
3 In reply Jesus declared, "I tell you the truth, no one can see the kingdom of God unless he is born again."
4 "How can a man be born when he is old?" Nicodemus asked. "Surely he cannot enter a second time into his mother's womb to be born!"
5 Jesus answered, "I tell you the truth, no one can enter the kingdom of God unless he is born of water and the Spirit.
6 Flesh gives birth to flesh, but the Spirit gives birth to spirit.
7 You should not be surprised at my saying, 'You must be born again.'
8 The wind blows wherever it pleases. You hear its sound, but you cannot tell where it comes from or where it is going. So it is with everyone born of the Spirit.”
The above scripture is explained partly by the following scripture:
Pistis Sophia
Chapter 115
"Now, therefore, he who shall receive the mysteries of the baptisms, then the mystery of them becometh a great, exceedingly violent, wise fire and it burneth up the sins and entereth into the soul secretly and consumeth all the sins which the counterfeiting spirit hath made fast on to it. And when it hath finished purifying all the sins which the counterfeiting spirit hath made fast on to the soul, it entereth into the body secretly and pursueth all the pursuers secretly and separateth them off on the side of the portion of the body. For it pursueth the counterfeiting spirit and the destiny and separateth them off from the power and from the soul and putteth them on the side of the body, so that it separateth off the counterfeiting spirit and the destiny and the body into one portion; the soul and power on the other hand it separateth into another. The mystery of baptism on the contrary remaineth in the midst of the two, continually separating them from one another, so that it maketh them clean and purifieth them, in order that they may not be stained by matter."
Now the identity of the mystery of the baptism is provided in The Apocryphon of James:
"Do you dare to spare the flesh, you for whom the spirit is an encircling wall?"
Therefore the spirit or Holy Spirit, is the mystery of the baptism who both purifies and encircles your soul, and accompanying spirit. Therefore when someone is born again / of the spirit, he is assigned the Holy Spirit who: purifies him through the process called "the mystery of the baptism"; lives in him (2 Timothy 1:14); and protects him.
In addition to above, please note that when someone is born, he is automatically born of the flesh. When this happens, his soul becomes a platform for an array of evil spirits, headed by a main counterfeiting spirit:
Pistis Sophia
Chapter 111
When then the Saviour had said this, he continued again in the discourse and said unto Mary: "Now, therefore, hearken, Mary, concerning the word on which thou hast questioned me: Who constraineth the man until he sinneth? Now, therefore, hearken: "Is the babe born, the power is feeble in it, and the soul is feeble in it, and also the counterfeiting spirit is feeble in it; in a word, the three together are feeble, without any one of them sensing anything, whether good or evil, because of the load of forgetfulness which is very heavy. Moreover the body also is feeble. And the babe eateth of the delights of the world of the rulers; and the power draweth into itself from the portion of the power which is in the delights; and the soul draweth into itself from the portion of the soul which is in the delights; and the counterfeiting spirit draweth into itself from the portion of the evil which is in the delights and in its lusts. And on the other hand the body draweth into itself the matter which senseth not, which is in the delights. The destiny on the contrary taketh nothing from the delights, because it is not mingled with them, but it departeth again in the condition in which it cometh into the world.
"And little by little the power and the soul and the counterfeiting spirit grow, and every one of them senseth according to its nature: the power senseth to seek after the light of the height; the soul on the other hand senseth to seek after the region of righteousness which is mixed, which is the region of the commixture; the counterfeiting spirit on the other hand seeketh after all evils and lusts and all sins; the body on the contrary senseth nothing unless it taketh up force out of the matter.
"And straightway the three develop sense, every one according to its nature. And the retributive receivers assign the servitors to follow them and be witnesses of all the sins which they commit, with a view to the manner and method how they will chastize them in the judgments.
"And after this the counterfeiting spirit contriveth and senseth all sins and the evil which the rulers of the great Fate have commanded for the soul, and it maketh them for the soul.
"And the inner power stirreth the soul to seek after the region of the Light and the whole god-head; and the counterfeiting spirit leadeth away the soul and compelleth it continually to do all its lawless deeds, all its mischiefs and all its sin, and is persistently allotted to the soul and is hostile to it, and making it do all this evil and all these sins.
"And it goadeth on the retributive servitors, so that they are witnesses in all the sins which it will make it do. Moreover also if it will rest in the night {or} by day, it stirreth it in dreams or in lusts of the world, and maketh it to lust after all the things of the world. In a word, it driveth {?} it into all the things which the rulers have commanded for it and it is hostile to the soul, making it do what pleaseth it not.
(Please note that the above is consistent with what I wrote here.) Further:
Gospel of Philip
"As for the unclean spirits, there are males among them and there are females. The males are they which unite with the souls which inhabit a female form, but the females are they which are mingled with those in a male form, through one who was disobedient. And none shall be able to escape them, since they detain him if he does not receive a male power or a female power - the bridegroom and the bride.One receives them from the mirrored bridal chamber. When the wanton women see a male sitting alone, they leap down on him and play with him and defile him. So also the lecherous men, when they see a beautiful woman sitting alone, they persuade her and comple her, wishing to defile her. But if they see the man and his wife sitting beside one another, the female cannot come into the man, nor can the male come into a woman. So if the image and the angel are united with one another, neither can any venture to go into the man or the woman."
(Please note that the image above is your soul, and the angel is the divine angel of the Holy Spirit - who is identified in the Bible as the Holy Spirit who lives in you.) Further:
Pistis Sophia
Chapter 140
"He continued in the discourse and said: "The second order is called Ariouth the Æthiopian, a female ruler, who is entirely black, under whom stand fourteen other [arch]demons which rule over a multitude of other demons. And it is those demons which stand under Ariouth the Æthiopian, that enter into strife-seekers until they stir up wars and murders arise, and they harden their heart and seduce it to wrath in order that murders may arise.
"And the souls which this authority will carry off in ravishment, pass one-hundred-and-thirteen years in her regions, while she tormenteth them through her dark smoke and her wicked fire, so that they come nigh unto destruction.
Counter to what is described above, when someone is born of the Spirit, he becomes a platform for an array of godly spirits who live in him and protect him:
Gospel of Philip
"The human being has intercourse with the human being. The horse has intercourse with the horse, the ass with the ass. Members of a race usually have associated with those of like race. So spirit mingles with spirit, and thought consorts with thought, and light shares with light. If you are born a human being, it is the human being which will love you.If you become a spirit, it is the spirit which will be joined to you. If you become thought, it is thought which will mingle with you. If you become light, it is light which will share with you. If you become one of those who belong above,it is those who belong above who will rest in you. If you become horse or ass or bull or dog or sheep or another of the animals which are outside and below, then neither human bein nor spirit nor thought nor light will be able to love you. Neither those who belong above nor those who belong within will be able to rest in you, and you have no part in them. He who is a slave against his will, will be able to become free."
Therefore being born again means that instead of your soul (which is a seed of God) remaining a platform for evil spirits who relentlessly defile you and force you to sin (resulting in the death of your soul), your soul becomes purified and protected by the Holy Spirit, and becomes a platform for godly spirits who cause you (and specifically your soul) to grow up as a baby or child god, bearing godly fruits. (See here for related information.)