The believer is "Born again of the Spirit" not of the flesh.
"Of the Spirit" doesn't mean your entirety wasn't reborn.
2 Cor 5:17..."Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new."
"All things are become new".
Substantiate your claim that if you sin you are not in Christ.
Gladly...
May we use "God" and "Jesus" interchangeably?
It is written..."This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all." (1 John 1:5) Pro 4:19 says "the way of the wicked is darkness", so their way is sinful...right?
Darkness is sin.
There is no sin in God, or in His Son who would not have been raised from the dead had He ever committed a sin.
Right?
Jesus said..."Which of you convinceth me of sin?" in John 8:46.
Paul wrote..."For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him." (2 Cor 5:21)
Do we agree that Jesus never committed a sin?
OK, let's proceed to our being in the perfectly sinless Jesus...
It is written..."And the glory which thou gavest me I have given them; that they may be one, even as we are one:
23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me." (John 17:22-23)
He is us and we in Him.
Right?
How?
It is written..."Know ye not, that so many of us as were baptized into Jesus Christ were baptized into his death?
4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
5 For if we have been planted together in the likeness of his death, we shall be also in the likeness of his resurrection:
6 Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin.
7 For he that is dead is freed from sin."
We are baptized into the perfectly sinless Jesus Christ, and "freed from sin".
We are one !
Just as Jesus commanded in Matt 5:48..."Be ye therefore perfect, even as your Father which is in heaven is perfect."
Our water baptism happens after repentance from sin. (Acts 2:38)
Repenting of sins makes us, by definition, non-sinners.
If we have turned from sin, how can we possibly still commit sin?
We turned from it !
So we have perfectly washed ex-sinners in Christ !
Will the unrepentant be in here?
NO
Will they who refuse baptism in the name of Jesus Christ for the remission of past sins be in here?
NO
Will murderers, liars, thieves, or adulterers be in here?
NO
The only ones in here, in Christ, are those who have obediently adhered to Peter's Acts 2:38 exhortation..."Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost."
The Holy Ghost will not reside in a corrupt temple.
1Jn 1:5-10 KJV
(5-6) This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all. If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
(7-8) But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin. If we say that we have no sin, we deceive ourselves, and the truth is not in us.
(9-10) If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness. If we say that we have not sinned, we make him a liar, and his word is not in us.
Did you notice the pattern?
John alternated verses addressing those who walk in darkness (sin) with verses addressing those who walk in light (God).
Verses 5, 7, and 9, address those walking in God, while verse 6, 8, and 10, address those walking in sin.
Sinners, those walking in darkness, cannot say they have no sin.
But those in verse 7, who have confessed their sins (v9), and had all their sins washed away by the blood of Christ can say they have no sins.
If they couldn't, it would be because the blood of Christ couldn't actually wash it away.
It can, and did for me and for everyone else now walking in the light...which is God, in whom is no darkness !
We are in Christ...if we walk in the light...in which is no sin.