Sin damages your relationship with God in regard to wilfull sin.
Yes, sin damages a relationship with God by the fact that it separates the believer from God and the salvation they have in Him.
Actually, there are several passages that tell us that you cannot be out of fellowship with God and be saved.
#1. 1 John 5:12 says He that has the Son has life and He that does not have the Son does not have life. Life is associated with eternal life or salvation.
#2. John 17:3 says eternal life is in knowing the one true God, Jesus Christ. Knowing implies a fellowship. So if you don't know Jesus, then you don't have life (Salvation).
#3. Romans 8:9 says if he a man does not have the Spirit of Christ, he does not belong to him.
#4. Psalms 73:27 says God will destroy all those who abandon Him (or go a whoring from Him).
#5. John 15:6 says if a man does not abide in Him, he is cast forth and burned.
#6. 1 John 1:7 says if we walk in the Light as He is in the Light, the blood of Jesus Christ cleanses us from all sin.
#7. Romans 11:21-22 says if you do not continue in his goodness you will be cut off. For if God spared not the natural branches (i.e. the Jews), take heed that he can do the same to you (i.e. Gentile believers). The analogy here is that you are branch and Christ is the tree. We need to continue in Christ's righteousness or goodness, not our own righteousness or goodness, or we will be cut off because of unbelief.
#8. 2 Corinthians 13:5 says,
"Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates."
You said:
Your conscience is seered as with a knife going through butter, for you are going against what is in your heart. You have no rest, and no peace until you come before your Father in heaven and repent of your folly.
Let's see what the Bible actually says about a conscience seared.
"Speaking lies in hypocrisy; having their conscience seared with a hot iron." (1 Timothy 4:2).
This is context to (a) departing from the faith and (b) doctrines of devils.
"Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils;" (1 Timothy 4:1).
You said:
The power of sin us the law. Live under it, and sins power remains firmly in place in your life.
By what you said so far, I understand you to be saying that you are under God's laws but you are not under these laws salvation wise (i.e. that keeping or breaking them has nothing to do with your salvation). The problem is that the Law is not a bad thing. The Law is holy, just, and good. God's intention was never for us to sin. The Law was supposed to be a school master or teacher that was supposed to bring us unto Christ. The Law of Moses was added because of transgressions. Man was get really sinful, so they needed a written Law in order for Man to be held more accountable to God. The Old Law was a way of showing their need for a Savior.
Jude 1:4 NIV condemns turning God's grace into a license for immorality.
Jesus still taught that keeping the commandments is life.
For Jesus says, "if thou wilt enter into life, keep the commandments." (Matthew 19:17).
And John says,
"In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother." (1 John 3:10).
"Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him." (1 John 3:15).
"For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved." (John 3:20).
"He that committeth sin is of the devil." (1 John 3:8).
You said:
So no, not being under law does not refer to initial salvation solely
I also said "Ultimate Salvation."
Also, the condition to not being under the Law is if you are led by the Spirit.
"But if ye be led of the Spirit, ye are not under the law." (Galatians 5:18).
Seeing the Spirit never wants a person to sin because the Spirit convicts the world of sin (John 16:8), one is not led by the Spirit if they think that not being under the Law means that they can commit serious sins and still be saved.
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