Our Christian walk is a "process", if we don't get this we increase our chances of being doomed to a life of doubting our salvation.
Those verses that would make me think that I am not saved where showing me what a mature Christian looks like. When we're babies, we cannot do what adult do and yet since we are human, we can learn and grow and through trial and error become, do and speak just like they do. If babies did not see people walking and talking, they would not learn to do these things themselves. God therefore, shows us who we are suppose to be inorder to inspire us and encourage growth, not to condemn and discourage us.
Having grown up a preachers kid and never being the rebellious type; I have believed Jesus to be the only Way, Truth and the Life as long I can remember. Therefore, I (other then what I will share later), don't have that black and white difference and clear cut contrast of before Christ and after Christ, like those who were delivered from drugs and a chaotic life a sin. For me it has been the slow process like a oak tree. I can't point to anyone moment and say "this was when I was born again" but as I look back I can definitely see that I have changed.
I am a firm believer that merely 'believing' the right things does not save, nor keeps one saved, Jesus told those who called him "Lord" to depart from him, for only those who do the will of the father shell enter into heaven. Even the demons know Jesus died, was buried and rose from the dead.
In 1st John, we read "these things were written that you could know that you have everlasting life". I have heard this verse preach, but NEVER in its context, for the context contradicts the common understanding of the grace through faith teaching. 1st John can be summed up in this "if you claim to know Christ and yet do not live like him, You are a liar and the truth is not in you, no matter what you think!" for in the Hebrew mindset, you do not believe something unless you do it. For example you do not believe Jesus died, unless you die to sin, you do not believe He was buried, unless you leave your sin behind and you don't believe He rose, unless (through Him) you walk in newness of Life. The book of 1st John helped me understand that just as People's friendship shape my life and interest. Likewise, if we know God, we will begin to enjoy what He enjoys and start doing what He does. And if not, then it is a sign we do not know Him.
I now see how God's word has become flesh in my life, affecting what I do, how I think, what I want and how I spend my time and money. Therefore, this gives me the assurance that I have been saved, and currently when I am living in harmony with Him, I can have assurance I am being saved and will be saved. But if I am living in deliberate sin, even though I may still be saved, I cannot have assurance that I am. I am sure that was all as clear as mud. : )
Becoming a Christian is a bit like getting married for there is a commitment and a binding contract. Even if a married couple, hurt and hate each other for periods of time, they are still married. Yet just as a divorce is possible, I think it is possible to loose ones salvation, but I don't think that if I chose to eat a piece of pie after I was already full and then had a car wreck ten minutes later that I would go to hell, anymore then if a man yells at his wife, then they would suddenly be unmarried. Scripture gives me the impression that if one looses their salvation they are forever damned and there is no second chance. This reminds me how Jesus said if one gets a divorce and later re-marries that it's adultery. I am just thinking out loud right now. Take it or leave it.
One thing that helps me to know I am saved is to look back and observe some contrast of now and then. When I was 13 and 14, I was addicted to pornography and I felt no shame or guilt, I loved it, I would look forward to going to bed in order to engage in fantasies, everything centered around this, it was what lived for. I am horrified when I think about the sicko things me and my best friend would talk about late at night. I see how my heart was such that even if I was free of temptation, I would still desire and long for this sinful escape and pleasure, for it was who I was at my core.
So what changed? When I began feeling some conviction and I got an accountability partner. Eventually lust was no longer something I lived for, but something I struggled with, though temptation and desire still cause me to want to sin at times, there is a difference. I was once dirty through and through, but now He has made me clean. While in this world I will get dirty but I can be cleaned. I know that if the temptation was taken away from me, I would never want to find pleasure through that vice again. When I am not intoxicated by desire and can see clearly I know the folly, emptiness and stupidity of this sin and never want to partake in it again.
And yet even still, sin is deceitful and the heart can be hardened, so I must be on my guard lest I fall away. Jesus told Peter that though he was clean, if Peter did not let Him wash his feet, that he could have no relationship with Him. Therefore, it makes it sounds like if we leave the filth on us and don't let Jesus sanctify us, eventually that dirt will penetrate and be a permanent stain. Kind of like a house constantly gets dirty, but remains livable if it is regularly cleaned. But within a few months of lack of maintenance, the stench and filth will be such that the whole house will need to be gutted or bulldozed.
I went through a long period where I was not sure that Christ lived within me, therefore my salvation was in question. I was wanting there to be something that I could do that would give me assurance, yet how could I know if I said the sinner’s prayer right or that I meant what I prayed with all my heart? And what is the heart? How on earth can I make the head knowledge go the 18 inches from my head to the heart? Can I break through my thick skull and rip it out and then stuff it in my blood pumping organ? I wanted to know I had faith, yet I could not even understand what faith was. I remember reading books on faith and yet nothing seemed to answer my questions. It is just one of the many Christian words we throw around that few can really expound on beyond the book answers
Now I see in that looking so intently at myself, I could not see the helmet of salvation that the Lord was offering me. The enemy would used the scripture to beat me across my head, causing me to doubt my salvation since I continued to look at my wretched self. It was not until I threw down the mirror and actually trusted that God really did love me enough and actually wanted to save me. This was very hard for me to do; the virus of Calvinism greatly compromised any confidence I once had of a loving God. Reformed theology caused me to fear that the reason I did not feel saved or could not find the strength to be godly and did not feel that I had the Holy Spirit was because He predestined me to hell and there was nothing I could do to change this reality.
But Ironically it was me reading something about even our "faith" is a gift from God and thus we're total hopelessness and spiritually bankruptcy before God and must throw ourselves upon his mercy, that finally lead me to cry out “Lord, even if You slay me, yet
I will trust you, you are my only hope.” and I really think this was a turning point for me.