Cause somebody taught them wrong ans they question themselves and think they must be misunderstanding scriptures that say otherwise.
1Ti 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.
Heb 5:9 And being made perfect, he became the author of eternal salvation unto all them that obey him;
Php 3:18 (For many walk, of whom I have told you often, and now tell you even weeping, that they are the enemies of the cross of Christ:
Php 3:19 Whose end is destruction, whose God is their belly, and whose glory is in their shame, who mind earthly things.
The Bible teaches time and time again that if you don't repent for your sins you perish. If you deny him, he denies you.
Only IF WE CONFESS does he forgive.
1 John 1
5This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.
6If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
7But if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus Christ his Son cleanseth us from all sin.
8If we say that we have no sin, we deceive ourselves, and the truth is not in us.
9If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
10If we say that we have not sinned, we make him a liar, and his word is not in us.
If we continue to live in sin we should be afraid. Very afraid.
Heb 10
23Let us hold fast the profession of our faith without wavering; (for he is faithful that promised;)
24And let us consider one another to provoke unto love and to good works:
25Not forsaking the assembling of ourselves together, as the manner of some is; but exhorting one another: and so much the more, as ye see the day approaching.
26For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
27But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
28He that despised Moses' law died without mercy under two or three witnesses:
29Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
30For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people.
31It is a fearful thing to fall into the hands of the living God.
Even if God has performed miracles through us if we turn our back on him and live in sin he will cast us out ("I never knew you" is a phrase that was used to disown/excommunite someone.)
Matthew 7
21Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
22Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works?
23And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
24Therefore whosoever heareth these sayings of mine, and doeth them, I will liken him unto a wise man, which built his house upon a rock:
25And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell not: for it was founded upon a rock.
26And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand:
27And the rain descended, and the floods came, and the winds blew, and beat upon that house; and it fell: and great was the fall of it.
Jude
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
24Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy,
25To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen.