I totally believe that when God saves us, we can never lose our salvation. Aside from the many verses posted here, we have to just think and be logical a bit.
God is perfect, just, holy and he is also omniscient, omnipotent and omnipresent. That basically puts God totally out of our league, forever! But, thanks be to God, he sent Jesus to die in our place on the cross. He redeemed us and paid our ransom for sin, and he was the ultimate and perfect atonemet for all our sins.
So, God, who sees all, knows all, and can do anything, saves us. (Of course, if you think you have saved yourself somehow, this won't apply to you!) Now this mighty, powerful, amazing and all-seeing and all-knowing God, knows and sees us, saves us, and gives us the desire to repent and follow him completely!
I can't see anywhere it says that after God has done this incredible work in our lives, he is going to look down from heaven and say, "Oops, I had no idea Jill Smith or Joe Martin were going to sin and turn away from me like this! Rats! I blew it, saving them when they didn't deserve to be saved. Let me look back on my list from before the foundation of the world to see why I thought they deserved to be saved. Oh my, how could I have missed this. They were going to do something I don't like. Hmm, let me see - how to make them be UNBORN from above. I will have to think about this."
Poor God, imagine him making mistakes all over the place about saving people, and then losing them.
But, just to be fair - we do have to walk with Christ and obey him. That means sometimes that the external things we do, because they reflect our hearts, are important. In other words we are not to sin! We need to keep our slate clean with God. Repent and confess to him. And ask forgiveness of those we have heard.
God gives us the strength to do this. Not because he is a meanie, but because he wants us to grow in holiness and obedience as we walk with him. So, no antinomianism, or lawlessness allowed. Not because we will lose our salvation, but because God does want us to continue to change, and go where the Holy Spirit is leading us.
As we have seen in 100's (or so it seems) of posts, salvation is not "grace vs the law." Salvation is all about God! God saves, us, leads, guides us, changes us, and keeps us. When I turned away from God for 2 years, because of the pain of untreated Rheumatoid Arthritis, and the terrible beating I took for "not having enough faith" from Word Faith people, I was hurt and angry. I could see no end to my pain, my walk with God seemed like it was over, along with my life. But God not only knew, he never left me. I cannot understand how such deliberate disobedience could have been passed over, but God was always there. The Holy Spirit kept speaking to me. He told me to read 5 Psalms a day. It took months before I would pick up my Bible and do it, but it was amazing how God used the Psalms and brought me out of that dark place, and used it all for his glory!
Yes, once saved, always saved, but never forget it has to come with geniune repentance and confession of sin. And "God is in control."