Can a sin lead one to hell even under grace? (this is not a Catholic post regarding mortal and venial sin)

A believer can fall from grace because of repeated and unrepentant sin. As a result, a believer can feel that they have offended the Holy Spirit and they no longer experience the peace of God that surpasses human understanding – the peace of being in communion with God. But does this mean the believer has lost their salvation and they are now going to hell? Not according to Holy Scripture.

Note the key word here is unrepentant sin. For a Christian who thinks they have free licence to sin whenever they like, tell a priest they are sorry and promise never to do it again, there must be a serious question as to whether they were ever saved in the first place. No true believer who has experienced the grace of God when they first came to saving faith could ever continue to willfully live in sin.

Yes, the believer can face temptation and can succumb to sinful thoughts and deeds. But God provides a way out. God’s children are given this sound advice in Philippians 4:6-7:

Do not be anxious about anything, but in everything, by prayer and petition, with thanksgiving, present your requests to God. And the peace of God, which transcends all understanding, will guard your hearts and your minds in Christ Jesus.

Salvation goes hand in hand with sanctification and justification. It is a process that continues throughout the life of the believer. What the believer can’t do, however, is earn salvation through their own efforts.

If we think we are saved by grace, but sanctified by our own efforts, we fall into error (Galatians 3:1–3). Sanctification is as much a work of God as justification. It is God who initiates salvation, who continues it and who will one day bring it to its consummation: “He who began a good work in you will carry it on to completion until the day of Christ Jesus” (Philippians 1:6). https://www.gotquestions.org/habitual-sin.html

Do you believe that promise of God or do you think you have to add to what God has already done? We have been justified (declared righteous by God), and now we have peace with God (Romans 5:1). Before that we were helpless (Romans 5:6), and we were enemies of God (Romans 5:10). But while we were still sinners, God showed his love for us by sending his Son, Christ Jesus, to die for us (Romans 5: 8). This is what the Bible has to say about our salvation:

I have been saved – in the past – from the penalty of sin – by a crucified Saviour: “For in this hope we were saved" (Romans 8:24). “For it is by grace you have been saved, through faith – and this not from yourselves, it is the gift of God” (Romans 2:8).

I am being saved – in the present – from the power of sin – by a living Saviour: "For the message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God" (1 Corinthians 1:18).

I shall be saved – in the future – from the presence of sin – by a coming Saviour: "Since we have now been justified by his blood, how much more shall we be saved from God's wrath through him!" (Romans 5:9)

If you think that “the Holy Spirit is getting away from me” then prayerfully approach the throne of grace in the name of Christ Jesus and plead to overcome your sinful desires through the enabling of the Holy Spirit to go forward in God’s power, in God’s strength, in God’s wisdom and in God’s grace. The the essence of the gospel is that Christ died for our sin (1 Corinthians 15:1–3). Because where sin abounded grace abounded more (Romans 5:20), we can have justification and new life through Jesus Christ by believing in Him. Romans 6:6-8 gives us this assurance:

We know that our old self was crucified with him in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin. For one who has died [to their old self] has been set free from sin. Now if we have died with Christ, we believe that we will also live with him.

Do you believe?