God told man:

But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely DIE (Gen. 2:17)

Satan said the opposite:

And the serpent said unto the woman, Ye shall NOT surely die (Ge. 3:4)

So God tells us that if we sin we will DIE, and Satan tells us that if we sin we will NOT DIE.  I fear that many people continue to spread the lies of  Satan even today without even realizing it. “Once saved always saved“, is such a lie and it has deceived millions (but there are also other false doctrines which Satan is using to deceive people; like the doctrine of the sinful nature and the doctrine of the imputed righteousness of Jesus). It has been a great hindrance to holiness and it’s undermining the fear of God. The teaching goes that once a person is truly a born again believer, then he will remain saved and can never fall away no matter what he does. Proponents of OSAS might immediately protest and say:

1) But true christians wouldn’t WANT to sin any more! They are born again and have new hearts! Now they are led by the spirit. We are not teaching that people who live in sin are saved. If they live in sin, they show that they were not saved to begin with.

but the same people might ALSO say:

2) We can never stop sinning! Also true christians will sin until they die. It’s just that christians don’t sin habitually, but only OCCASIONALLY, and they don’t commit any severe sins. But they are still saved.

The dilemma is obvious. Also true born again christians might choose to sin, but will such a person automatically repent after his sin? Not necessarily. If not even King David repented until about a year after his sins (adultery and murder) in relation to Bathsheba, why would we believe WE are exempted from this peril? If we can avoid sinning for days and weeks, we can also stop sinning for months and years. Each time we sin, we could have chosen not to sin. King David was a person who cannot be filed under “he wasn’t saved to begin with”  since he was a man of God’s own heart and a true child of God, and yet he fell away due to sin and died spiritually. The Bible is full of warnings to true believers that they might be cut off the vine tree (Jesus) and similar expressions.

We are still warned that sin causes spiritual DEATH

Ezekiel 18:20-24 The soul that sinneth, it shall die. The son shall not bear the iniquity of the father, neither shall the father bear the iniquity of the son: the righteousness of the righteous shall be upon him, and the wickedness of the wicked shall be upon him. But if the wicked will turn from all his sins that he hath committed, and keep all my statutes, and do that which is lawful and right, he shall surely live, he shall not die. All his transgressions that he hath committed, they shall not be mentioned unto him: in his righteousness that he hath done he shall live. Have I any pleasure at all that the wicked should die? saith the Lord GOD: and not that he should return from his ways, and live? But when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he DIE.

Rom 6:21 What benefit did you reap at that time from the things you are now ashamed of? Those things result in DEATH!

Romans 6:16: Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin UNTO DEATH, or obedience unto righteousness.

1 Pet 2:11 Dear friends, I urge you, as aliens and strangers in the world, to abstain from sinful desires, which war against your SOUL.

Romans 8: ⁶For to be carnally minded is DEATH; but to be spiritually minded is life and peace. ⁷Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be. ⁸So then they that are in the flesh cannot please God. —¹³For if ye live after the flesh, YE SHALL DIE: but if ye through the Spirit do mortify the deeds of the body, YE SHALL LIVE. 

James 5:¹⁹Brethren, if any OF YOU do err from the truth, and one convert him; ²⁰Let him know, that he which converteth the sinner from the error of his way shall save a soul from DEATH, and shall hide a multitude of sins.

John 3:36 He who believes in the Son has eternal life; but he who does not obey the Son WILL NOT SEE LIFE, but the wrath of God abides on him.

Mark 9:47.And if your eye causes you to sin, pluck it out. It is better for you to enter the kingdom of God with one eye than to have two eyes and be thrown into HELL

Matt. 7:21 Not everyone who says to me Lord, Lord, will enter the kingdom of heaven, but only he who DOES the will of my Father who is in heaven.

1 Peter 4:18 And if it is with difficulty that the righteous is saved, what will become of the godless man and sinner?

The word of Jesus

Matthew 5:13 Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.

Matthew 13:21 Yet hath he not root in himself, but dureth for a while: for when tribulation or persecution ariseth because of the word, by and by he is offended…which for a while believe, and in time of temptation fall away.

Luke 8: ¹³They on the rock are they, which, when they hear, receive the word with joy; and these have no root, which for a while believe, and in time of temptation fall away. 

John 8:31 …IF ye continue in my word, then are ye my disciples indeed.—34-35 Jesus answered them, Verily, verily, I say unto you, Whosoever committeth sin is the servant of sin. And the servant abideth not in the house for ever: but the Son abideth ever.

John 16:¹These things have I spoken unto you, that ye should not be offended.

Mat 11:⁶And blessed is he, whosoever shall NOT be offended in me.

Matt. 24:10And then shall many be offended, and shall betray one another, and shall hate one another. ¹¹And many false prophets shall rise, and shall deceive many. ¹²And because iniquity shall abound, the love of many shall wax cold. ¹³But he that shall endure unto the end, the same shall be saved.

Matt 10:³²Whosoever therefore shall confess me before men, him will I confess also before my Father which is in heaven. ³³But whosoever shall deny me before men, him will I also deny before my Father which is in heaven. —³⁷He that loveth father or mother more than me is not worthy of me: and he that loveth son or daughter more than me is not worthy of me. ³⁸And he that taketh not his cross, and followeth after me, is not worthy of me.

Matt 26:³¹Then saith Jesus unto them, All ye shall be offended because of me this night: for it is written, I will smite the shepherd, and the sheep of the flock shall be scattered abroad. ³²But after I am risen again, I will go before you into Galilee. ³³Peter answered and said unto him, Though all men shall be offended because of thee, yet will I never be offended. ³⁴Jesus said unto him, Verily I say unto thee, That this night, before the cock crow, thou shalt deny me thrice.

Mat 18:33 Shouldest not thou also have had compassion on thy fellowservant, even as I had pity on thee? 34 And his lord was wroth, and delivered him to the tormentors, till he should pay all that was due unto him. 35 So likewise shall my heavenly Father do also unto you, if ye from your hearts forgive not every one his brother their trespasses.

Security comes through faith and obedience to God’s grace, not disobedience

John 15¹I am the true vine, and my Father is the husbandman. ²Every branch in me that beareth not fruit he taketh away: and every branch that beareth fruit, he purgeth it, that it may bring forth more fruit. ³Now ye are clean through the word which I have spoken unto you. ⁴Abide in me, and I in you. As the branch cannot bear fruit of itself, except it abide in the vine; no more can ye, except ye abide in me. ⁵I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing. ⁶If a man abide not in me, he is cast forth as a branch, and is withered; and men gather them, and cast them into the fire, and they are burned. ⁷If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you. ⁸Herein is my Father glorified, that ye bear much fruit; so shall ye be my disciples. ⁹As the Father hath loved me, so have I loved you: continue ye in my love. ¹⁰If ye keep my commandments, ye shall abide in my love; even as I have kept my Father’s commandments, and abide in his love. ¹¹These things have I spoken unto you, that my joy might remain in you, and that your joy might be full. 

1. Jesus is speaking to 11 chosen apostles. Judas had already left, and the remaining 11 were chosen and IN Christ.
2. Jesus specifically says “you are already clean” to the apostles.
3. Jesus commands them to ABIDE in Him, because they cannot bear fruit unless they do. It’s not certain they will abide.
4. Jesus warns the chosen apostles that if they do not abide in Him, the Father will cut them off, and the branches will be gathered and cast into the fire.
5. The branches will dry up/wither, indicating that they used to have LIFE
6. Jesus says “IF” you keep my commandments, you “WILL” ABIDE in my love (conditional)

1 Cor. 15:2 By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in VAIN

1 Cor 3:¹⁶Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you? ¹⁷If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.

2 Cor 13:5  Examine yourselves, whether ye be in the faith; prove your own selves. Know ye not your own selves, how that Jesus Christ is in you, except ye be reprobates?

Heb 3:12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.

Hebr 10: 29 How much more severely do you think a man deserves to be punished who has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace?

Gal. 1:⁶I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel

Galatians 5:4 Christ is become of no effect unto you, whosoever of you are justified by the law; ye are FALLEN FROM GRACE

Philip. 2:12 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling.

1 Thes. 3:8 For now we live, IF ye stand fast in the Lord.

1 Tim. 1:5-6 Now the end of the commandment is charity out of a pure heart, and of a good conscience, and of faith unfeigned: From which some having swerved have turned aside unto vain jangling

1 Tim. 4:1 Now the Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils

1 Tim. 4:16 Take heed unto thyself, and unto the doctrine; continue in them: for in doing this thou shalt both save thyself, and them that hear thee

2 Tim. 2:18 Who concerning the truth have erred, saying that the resurrection is past already; and OVERTHROW THE FAITH OF SOME. There are many, many more scriptures just like these throughout the Bible, due to lack of space I will list them at the end of this study and you may look them up.

Romans 11:20-22 Well; because of unbelief they were broken off, and thou standest by faith. Be not highminded, but fear: For if God spared not the natural branches, take heed lest he also spare not thee. Behold therefore the goodness and severity of God: on them which fell, severity; but toward thee, goodness, if thou continue in his goodness: otherwise thou also shalt be cut off.

James 1:¹²Blessed is the man that endureth temptation: for when he is tried, he shall receive the crown of life, which the Lord hath promised to them that love him.

2Pe 2:20 For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them. 22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.

2 Peter 3:¹⁶As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction. ¹⁷Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness.

1 John 3:⁷Little CHILDREN, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous. ⁸He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.

2 John 1:⁹Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son.

Jude 1:⁵I will therefore put you in remembrance, though ye once knew this, how that the Lord, having saved the people out of the land of Egypt, afterward destroyed them that believed not. ⁶And the angels which kept not their first estate, but left their own habitation, he hath reserved in everlasting chains under darkness unto the judgment of the great day

Rev 2:5 Remember therefore from whence thou art fallen, and repent, and do the first works; or else I will come unto thee quickly, and will remove thy candlestick out of his place, except thou REPENT. 

Rev 3: ¹⁰Because thou hast kept the word of my patience, I also will keep thee from the hour of temptation, which shall come upon all the world, to try them that dwell upon the earth. ¹¹Behold, I come quickly: hold that fast which thou hast, that no man take thy crown. ¹²Him that overcometh will I make a pillar in the temple of my God, and he shall go no more out: and I will write upon him the name of my God, and the name of the city of my God, which is new Jerusalem, which cometh down out of heaven from my God: and I will write upon him my new name

Rev 3:16 So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.

Rev 22:19 And if any man shall take away from the words of the book of this prophecy, God shall take away his part out of the book of life, and out of the holy city, and from the things which are written in this book. 

Rev. 3:⁴Thou hast a few names even in Sardis which have not defiled their garments; and they shall walk with me in white: for they are worthy. ⁵He that overcometh, the same shall be clothed in white raiment; and I will not blot out his name out of the book of life, but I will confess his name before my Father, and before his angels. 

Jeremiah 15:6-7 Thou hast forsaken me, saith the LORD, thou art gone backward: therefore will I stretch out my hand against thee, and destroy thee; I am weary with repenting. And I will fanthem with a fan in the gates of the land; I will bereave them of children, I will destroy my people, since they return not from their ways.

Psa. 125:5 Those who turn to crooked ways the LORD will banish with the evildoers.

Hosea 9: ¹⁵All their wickedness is in Gilgal: for there I hated them: for the wickedness of their doings I will drive them out of mine house, I will love them no more: all their princes are revolters.

Before their sin in Exodus many Israelites were born again (Dt 32:18, Gal 4:28-29), they were redeemed (Ex 15:13, Dt 21:8), they were sanctified (Ex 31:13, Dt 21:8), they were converted (Ps 19:7), they were in grace (Ex 33:12-17, Ps 19:7, Ps 84:11), had their names in the book of life (Ex 32:32-33, Ps 69:25-29), had the same gospel we have (Gal 3:6-14, Heb 4:2), yet when they sinned the were cut off from God and were lost (Ex 32:32-33, 1 Cor 10:1-18, Heb 4:1-7, Jude 1:5).  (Thanks to Britt Williams)

“It is astonishing how people talk about perseverance. As if the doctrine of perseverance were: ‘Once in grace, always in grace’; or , ‘Once converted, sure to go to heaven.’ This is not the idea of perseverance. The true idea is, that if a man is truly converted, he will, as a rule, continue to obey God; and, as a consequence, he will surely go to heaven. But if a person gets the idea that because he is ‘converted,’ therefore he will assuredly go to heaven, that man will almost assuredly go to hell.” //Charles G. Finney