Once saved is always saved states that once a person is truly saved through repentance and faith in Jesus (Romans 10:9), his or her salvation can never be lost no matter how badly or how often that person sins after salvation. Many times in Scripture we are told to continue, or to persevere in our faith.
True salvation is one has to develop faith in Christ, repent of their sins, baptized for the remission of their sins, received the gift of the Holy Ghost. Live the commandments of God. Salvation is a continuous process” but he who stands firm to the end will be saved.”
Philippians 2:12-13:Therefore, my dear friends, as you have always obeyed—not only in my presence, but now much more in my absence—continue to work out your salvation with fear and trembling, for it is God who works in you to will and to act according to his good purpose.
The Bible does not guarantee salvation to those living wickedly; the only assurance of salvation is by good works (Ps 15:1-5; Matt 7:21-23; John 8:31-32; II Cor 5:17; Phil 2:12-16; Titus 3:8; Jas 1:26-27; I John 2:4; 3:10).
1.Sin separates us from God:
Isaiah 59:2 But your sinful acts have alienated you from your God; your sins have caused him to reject you and not listen to your prayers.
Galatians 5:19-21 :The acts of the sinful nature are obvious: sexual immorality, impurity and debauchery; 20idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions 21and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.
1 John 3:8 He 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
Proverbs 30:12 There is a generation that are pure in their own eyes, and yet is not washed from their filthiness.
Isaiah 13:11 And I will punish the world for their evil, and the wicked for their iniquity; and I will cause the arrogancy of the proud to cease, and will lay low the haughtiness of the terrible.
Amos 3:2 You only have I known of all the families of the earth: therefore I will punish you for all your iniquities.
Ezekiel 21:24 Therefore thus saith the Lord GOD; Because ye have made your iniquity to be remembered, in that your transgressions are discovered, so that in all your doings your sins do appear; because, I say, that ye are come to remembrance, ye shall be taken with the hand.
2 Peter 2:14 Having eyes full of adultery, and that cannot cease from sin; beguiling unstable souls: an heart they have exercised with covetous practices; cursed children:
1 Corinthians 6:9-10 Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.
Ezekiel 18:4 Behold, all souls are mine; as the soul of the father, so also the soul of the son is mine: the soul that sinneth, it shall die.
2.One can fall away from faith.
Hebrews 6:4-6 "For in the case of those who have once been enlightened and have tasted of the heavenly gift and have been made partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, and then have fallen away, it is impossible to renew them again to repentance, since they again crucify to themselves the Son of God, and put Him to open shame."
Hebrews 10:26-27 "For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain terrifying expectation of judgment, and the fury of a fire which will consume the adversaries."
Hebrews 10:38-39 "But My righteous one shall live by faith; And if he shrinks back, My soul has no pleasure in him. But we are not of those who shrink back to destruction, but of those who have faith to the preserving of the soul."
Luke 8:13 Those on the rock are the ones who receive the word with joy when they hear it, but they have no root. They believe for a while, but in the time of testing they fall away.
Colossians 1:21-23 Once you were alienated from God and were enemies in your minds because of your evil behavior. But now he has reconciled you by Christ's physical body through death to present you holy in his sight, without blemish and free from accusation -- if you continue in your faith, established and firm, not moved from the hope held out in the gospel. This is the gospel that you heard and that has been proclaimed to every creature under heaven, and of which I, Paul, have become a servant.
Romans 11:22 Consider therefore the kindness and sternness of God: sternness to those who fell, but kindness to you, provided that you continue in his kindness. Otherwise, you also will be cut off.
John 15:5-6 I am the vine; you are the branches. If a man remains in me and I in him, he will bear much fruit; apart from me you can do nothing. If anyone does not remain in me, he is like a branch that is thrown away and withers; such branches are picked up, thrown into the fire and burned.
1 Corinthians 15:2 By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain.
Revelation 3:5 All who are victorious will be clothed in white. I will never erase their names from the Book of Life, but I will announce before my Father and his angels that they are mine. This verse shows You can fall from grace, your name can be erased. Even though it was there, written in the Lamb's Book of Life, it can be taken out.
Hebrews 10:26-29 For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins,but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries. Anyone who has rejected Moses’ law dies without mercy on the testimony of two or three witnesses.Of how much worse punishment, do you suppose, will he be thought worthy who has trampled the Son of God underfoot, counted the blood of the covenant by which he was sanctified a common thing, and insulted the Spirit of grace?
John 15:2, 6: Every 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... If 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.