After a very long and tiered conversation with someone who thinks they can lose their salvation, I will post this list [shamelessly stolen from Melvin's Essays] Link is Here.
Here is what must happen every time you sin and LOSE your salvation.
1. I have to lose my eternal life – which, or course, isn’t eternal if I can lose it.
2. I have to cease to be the new creation and become an old creation again.
3. I have to cease to be a child of God – He has to disown me.
4. I have to again become a child of wrath.
5. I have to cease to be a child of Light and become a child of darkness again.
6. I have to be removed from the body of Christ – un-baptized as it were.
7. I have to come alive again, outside of Christ.
8. I have to get unburied and un-united in my burial with Christ.
9. I have to take myself out of Jesus’ hand.
10. I have to take myself out of the Father’s hand.
11. I have to be transferred back to the kingdom of darkness.
12. I have to be unsealed for the day of redemption.
13. I have to some how come alive again to the power of sin.
...and of course, after I have repented, God does it all over again! Yeh, ok...
5 He saved us, not on the basis of deeds which we have done in righteousness, but
according to His mercy, by the washing of regeneration and renewing by the Holy Spirit,
Our actions are indicators of God's saving grace, not the reason [why] we are saved.
Romans 8:30 - And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified.
From the moment God choses us, we are as good as being in His presence in heaven.
Romans 8:38-39 - For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, 39 neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord.
Some may say - "But "I" can walk away from God". Unless man is not a "creation", then yes. The point of this verse is utter assurance in God's work.