Let me state, hopefully not insulting anyone, that I hate cigarette smoke! My grandmother's house was filled with yellow smoke, to match her yellow stained fingers, as she chained smoked her way through each day. She was a sweet old lady, but in the thrall of that addiction. And smoking probably helped kill my paternal grandfather.
But mostly I hate it because I am severely allergic to it! I can't count the number of time I've been walking down the street and inhaled second hand smoke before I realized someone was smoking, and had to go to the ER for treatment. Before I was saved, I played in bars, and that was when smoking in bars was still legal. I lost my voice on Monday night, usually by the beginning of the second set. And my voice stayed lost till I went home, and had fresh air to breath.
So, I hate second hand cigarette smoke! BUT, is it a sin? Does it separate you from God? I suppose it depends on your understanding of soteriology, your conviction smoking is wrong, and what kind of person you are. There are addictive personalities. It is so much harder for them to quit something addictive. In fact, heroin addicts saying quitting heroin was easier than quitting smoking! God set me from my alcohol addiction, but if I take opiates, frequently called for with my chronic pain (and doctor prescribed!) I can stop instantly. I have weaned off of prednisone easily, many times, and stayed off till another med failure, many years later. I weaned off of prednisone as the new meds started working, by just keeping track of the dose and lowering it every first or second week. So, no addictions here!
So, what I see is an OP who wants to quit, but has had no luck. He also feels condemned by an SDA pastor. Hmm! They condemn eating meat, too! For very good reasons, and very good results! But some people need meat, because of their body type. I am not one of those types, but do I condemn people who do eat meat? Well, not any more! LOL I've been a vegetarian now for 46 years and I'm very glad about it! Are other people going to lose their salvation because they eat meat! Never!
As far as the issue of how we are saved, and whether we can lose our salvation, there are probably 20 recent threads on this. There are two sides, and I stand squarely on the side of God saving us, forever! So eternal security! But, I also agree that we do need to follow Jesus, obey him, as a sign that we are truly saved. I'm not going to judge someone who believes differently, but I will step in when people feel so judged and condemned they fear every move they make is a sin, and will send them straight to hell.
Look up eternal security and read about it! But if you come up disagreeing, you may find most theologians on the Arminian side, do not think that anyone can lose their salvation the minute they light up a cigarette. Arminians believe you can lose your salvation if you willfully sin, and do not follow Jesus. John says, if someone does that, they probably were never saved in the first place.
"They went out from us, but they did not belong to us; for if they had belonged to us, they would have remained with us. However, they went out so that it might be made clear that none of them belongs to us." 1 John 2:19
My thought is to stop listening to internet preachers of any sort. Especially judgmental SDA ones (I do believe they are saved, but then trap themselves in legalism!). Instead, read the Bible daily! Pray and read it. Study it! Read 3 chapters of the OT and one of the NT and you get through the Bible in a year. See what God says to you.
And yes ask God to help you quit smoking forever. But also see you're doctor, as their are many tricks you can employ, and even medications to help you. Every time I phone my pharmacy I get a little blurb I wish I could skip over, about a stop smoking program that the BC government will pay for.
If you feel such conviction here, I do think God is talking to you about quitting. But that conviction is not that you are going to lose your salvation!
"For you are saved by grace through faith, and this is not from yourselves; it is God’s gift— 9 not from works, so that no one can boast." Eph. 2:8-9.
Just as you cannot save yourself by works, neither can you lose your salvation by works or even sin! We are all sinners saved by grace! So why quit then, besides the tremendous health benefits? Well, because God is telling you to! Focus on that, and please pick up a Bible and read it, ok?