Jesus explained about this and it is recorded in John 3
John
3:1 There was a man of the politicians, named Nicodemus, a ruler of the Jews:
3:2 The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
3:3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born from above, he cannot SEE the Kingdom of God.
3:4 Nicodemus saith unto him, How can a man be born when he is old? Can he enter the second time into his mother's womb, and be born?
3:5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water (human) and then is born (later) from above as his spirit-"Being" (his REAL self which is NOT human), he can NOT enter into the Kingdom of God (Who is a Spirit-"Being").
3:6 That which is born of the flesh is human; and that which is born of the Spirit is spirit (a spirit-"Being") - (a human+Being).
3:7 Marvel not that I said unto thee, Ye must be born again.
3:8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and where it goeth: so is every one that is born of the Spirit.
3:9 Nicodemus answered and said unto him, How can these things be? (How can I not be human?)
3:10 Jesus answered and said unto him, Art thou a teacher of Israel, and knowest not these things?
3:11 Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness.
3:12 If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you [of] heavenly (spirit) things?
King of kings Bible.
The Gospel of Thomas goes into further detail about being spiritually reborn, but most christians of course won't read it because the church tells them not to.
The religious people of Jesus day accused Him of having a devil, when all the time He had been telling them the truth:
8:39 Then answered the Jews, and said unto him, Say we not well that thou art a Samaritan, and hast a devil?
8:40 Jesus answered, I have not a devil; but I honour my Father, and ye do dishonour me.
8:41 And I seek not mine own glory: there is one that seeketh and judgeth.
8:42 Verily, verily, I say unto you, If a man keep my saying, he shall never see "Death".
8:43 Then said the Jews unto him, Now we know that thou hast a devil. Abraham is dead, and the prophets; and thou sayest, If a man keep my saying, he shall never taste of death.
Thomas
1:1 These are the coded words which the Living Jesus spoke and Didymos (twin) Judas Thomas wrote.
1:2 And He said: Whoever finds the explanation of these words will not taste death.
3 Articles about spiritual rebirth -
https://hannahmichaels.wordpress.com/tag/being-spiritually-reborn/
It's sad how susceptible people are to thinking evil, and it is because of listening to the wrong voice - the evil one, instead of listening to the Good Voice (God's Voice).
A good line to remember is:
"Honi soit q mal ye pense" - Evil be to him who thinks it.