Rom 12:1; Therefore I urge you, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your reasonable spiritual service of worship.
Rom 12:2; And do not be conformed to this world, but be transformed by the renewing of your mind, so that you may prove what the will of God is, that which is good and acceptable and perfect.
Present you bodies as a sacrifice... acceptable to God. This isn't a "work". It isn't something that you do
"to get" saved. It's what you should be doing "after" you are saved.
This is just your "reasonable service service" to God. Not a "work" to get saved.
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Php 2:12; So then, my beloved, just as you have always obeyed, not as in my presence only, but now much more in my absence, work out your salvation with fear and trembling;
Php 2:13; for it is God who is at work in you, both to will and to work for His good pleasure.
God worked for the Israelites when they fled Egypt. It was His work. The Israelites didn't cause Manna
to fall from heaven. They didn't cause a cloud to lead them. They didn't part the red sea.
God did these things. But they were still able to grumble and build a golden calf idol.
This "disobedience" kept them from entering the promised land. ( Heb 3:18; )
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Some take only John 3:16 is all that is required for eternal life.
Yet Jesus said... If you want to have eternal life, keep the commandments ( Matt 19:17; )
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Both sides agree we 'should" be living righteously, and it's not righteous living that saves us.
The only real difference here is...
Whatever might be part of our walk... our oil in lamp, our saltiness, our faith, our obedience,
we have the ability, the choice, to quit doing those things.
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2 Pet 2:19; promising them freedom while they themselves are slaves of corruption; for by what a man is overcome, by this he is enslaved.
2 Pet 2:20; For if, after they have escaped the defilements of the world by the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and are overcome, the last state has become worse for them than the first.
2 Pet 2:21; For it would be better for them not to have known the way of righteousness, than having known it, to turn away from the holy commandment handed on to them.
2 Pet 2:22; It has happened to them according to the true proverb, “A dog returns to its own vomit,” and, “A sow, after washing, returns to wallowing in the mire.”
We have the ability, if we desire... to go back to the vomit and pig-sty we came from.
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I don't think this happens by accident. I don't even think it happens quickly.
A popular Christian song a few years ago said .. "It's a slow fade". People never crumble in a day.
You don't sin a few times and get un-saved.
It's a conscious choice. A willfull disobedience. A personal decision to not follow God anymore.
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Verses 19 and 20 in 2 Peter above talk about being "overcome" by evil after you are already a Christian.
We can't overcome the world on our own... it requires Jesus. But even with Jesus it requires obedience and
decisions. It requires taking up your cross "daily".
It requires overcoming. ( Rev 2:7; Rev 2:11; Rev 2:17; Rev 2:26; Rev 3:5; Rev 3:12; Rev 3:21; Rev 21:7; etc.. )
It requires fighting the good fight and finishing the course ( 2 Tim 4:7; )
It requires running the race that is set before us. ( Heb 12:1; )
It requires laying aside "the sin which so easily entangles us". ( Heb 12:1; )
We need to run this race in such as way as to win. ( 1 Cor 9:24; )
It requires being a good and faithful steward of the responsibilities God has given us ( Matt 25:21; Matt 25:23; )
If we aren't a good servant, if we go back to doing evil... the master will assign us to a place "with" the unbelievers. ( Luke 12:46; )
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Satan goes around like a roaring Lion to see who he can devour. He doesn't have to devour the unsaved. They already belong to him.
Why are Christians tempted? Why do we go through trials? Why are we tested? So that we can know where we stand.
If we're always failing in temptation, and always failing the test of faith... it isn't God's fault.
That's wy we need to overcome, fight the good fight, run the good race, keep oil in our lamp, and take up our cross "daily".
Jesus doesn't point to you and say "poof" you're saved forever. He says you are saved right now. Go and sin no more so that nothing worse happens to you.