It baffles me that Christians can dare think they can lose their salvation when it is clearly indicated in Scripture that you cannot. It seems borderline heretical. Plus, when you question your salvation one of a few things surface:
First: Christianity would become a religion of legalism and works. We do not earn salvation, it is a GIFT from God. Yes, we ask for it ane receive it when we do but it is final! According to Epheasians 2:8- we are saved by grace NOT OF WORKS lest anyone should boast. This where the question of an unforgivable sin may come up, or the possibility of walking away (found in Hebrews ). But one thing would account for walking away: FALSE CONVERSION if you truly meant turning to Christ, one would think you would not slip away when times get tough. When we confess our sins, we are forgiven. Once and for all. When we ask
Second: Forgiveness from sins would only be made possible via Old Covenant sacrifces. The life of Jesus did not necessarily replace or counteract burning sacrifces but fulfilled the Old Law. John 14:6- Jesus said: I am the way, the truth and the life. No one comes to the father except through me.
Third: what would Jesus of died for? His ministry, life, death and ressurection made salvation possible and more accessible for everyone but with this apoasacy issue questions of divine election, too much sinning and the unforgiavable sin come up. Yes, greieving the Holy Spirit is a sin, lets look at what it is (according to Christianity Today): to hinder a godly lifestyle. Both happen when a believer sins against God and follows his or her own worldly desires. The only correct road to follow is the road that leads the believer closer to God and purity, and farther away from the world and sin. Just as we do not like to be grieved, and just as we do not seek to quench what is good—so we should not grieve or quench the Holy Spirit by refusing to follow His leading.
Turning away from faith and puposely continuing in particuar sins dies not affext your salvation, although we are forgiven, do we think that God would allow us to choke on it? 1 Corinthians 10:13- No temptation has overtaken you except such as is common to man; but God is faithful, who will not allow you to be tempted beyond what you are able, but with the temptation will also make the way of escape, that you may be able to bear it
To conclude: believing or not one can lose salvation does not affect your own salvation. The only thing that matters is that you are sealed by the Holy Spirit, written in the book of Life and that you have trusted Jesus with all of your heart, mind and soul. (obviously you can see my opinion on the matter: you cannot lose salvation).