The Bible teaches that to be saved we must:
1. Believe the gospel preached by Jesus and his apostles.
2. Repent of our sinful way of life – that is: change the way that we live.
3. Be baptised by immersion in water into Jesus Christ for the remission of past sins.
4. Live a new life by the commandments of Jesus Christ
5. Hold fast to the end of our lives.
Mark 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature. 16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned (condemned).
We are not saved until the day of resurrection and judgment.
2 Corinthians 5:10 For we must all appear before the judgment seat of Christ; that every one may receive the things done in his body, according to that he hath done, whether it be good or bad.
The doctrine of ‘once saved, always saved’ is a false doctrine not found in the Bible. Similarly, the ‘sinner’s prayer’ is not found in the Bible.
The ‘parable of the sower’ (Matthew 13) illustrates the situation of those who hear the gospel.
Matthew 13:18 Hear ye therefore the parable of the sower 19 When any one heareth the word of the kingdom, and understandeth it not, then cometh the wicked one, and catcheth away that which was sown in his heart. This is he which received seed by the way side. 20 But he that received the seed into stony places, the same is he that heareth the word, and anon with joy receiveth it; 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. 22 He also that received seed among the thorns is he that heareth the word; and the care of this world, and the deceitfulness of riches, choke the word, and he becometh unfruitful. 23 But he that received seed into the good ground is he that heareth the word, and understandeth it; which also beareth fruit, and bringeth forth, some an hundredfold, some sixty, some thirty.
When we believe the gospel, repent of our sinful way of life (change the way we live) and are baptised by immersion in water, all our past sins are washed away.
Acts 2:38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins…
Acts 22:16 And now why tarriest thou? arise, and be baptized, and wash away thy sins, calling on the name of the Lord.
Following baptism, we arise sinless out of the water to begin a new life.
Romans 6:4 Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
Our new life is to be lived by the commandments of Jesus Christ.
John 15:14 Ye are my friends, if ye do whatsoever I command you.
Luke 6:46 And why call ye me, Lord, Lord, and do not the things which I say?
We cannot live a sinless life (otherwise Jesus need not have died).
After baptism we will still sin, but, providing we are making a determined effort to live by the commandments of Christ, our sins will be forgiven by confession in prayer.
1 John 1:7 But 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. 8 If we say that we have no sin, we deceive ourselves, and the truth is not in us. 9 If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness.
To be saved we must hold fast to our faith until we die.
Matthew 24:13 But he that shall endure unto the end, the same shall be saved.
The writer to the Hebrews warns those who had received supernatural powers as a gift of the Holy Spirit, that if they fell away there was no way back.
Hebrews 6:4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Spirit, 5 And have tasted the good word of God, and the powers of the world to come, 6 If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame. 7 For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God: 8 But that which beareth thorns and briers is rejected, and is nigh unto cursing; whose end is to be burned.
He warns against ‘wilful sin’.
Hebrews 10:26 For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, 27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. 28 He that despised Moses’ law died without mercy under two or three witnesses: 29 Of 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?... 38 Now the just shall live by faith: but if any man draw back, my soul shall have no pleasure in him. 39 But we are not of them who draw back unto perdition; but of them that believe to the saving of the soul.
Paul instructs the Philippians to ‘work out their salvation ‘with fear and trembling’:
Philippians 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.
Paul did not consider himself saved until the end of his life.
Philippians 3:11 If by any means I might attain unto the resurrection of the dead. 12 Not as though I had already attained, either were already perfect: but I follow after, if that I may apprehend that for which also I am apprehended of Christ Jesus. 13 Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before, 14 I press toward the mark for the prize of the high calling of God in Christ Jesus.
He writes to the Corinthians:
1 Corinthians 9:27 But I keep under my body, and bring it into subjection: lest that by any means, when I have preached to others, I myself should be a castaway.
If it was possible for Paul himself to be a castaway, the doctrine of ‘once saved always saved’ is shown to be false.
At the end of his life he writes to Timothy:
2 Timothy 4:6 For I am now ready to be offered, and the time of my departure is at hand. 7 I have fought a good fight, I have finished my course, I have kept the faith: 8 Henceforth there is laid up for me a crown of righteousness, which the Lord, the righteous judge, shall give me at that day: and not to me only, but unto all them also that love his appearing.
Paul writes of others who ‘made shipwreck’ of their faith, whom he had disfellowshipped.
1 Timothy 1:19 Holding faith, and a good conscience; which some having put away concerning faith have made shipwreck;
In Christ’s letters to the seven churches in Revelation ‘falling away’ is seen to be happening in them.
A general falling away within the Church is prophesied:
2 Thessalonians 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
The falling away of the early Church was completed by the fourth century when the Church became the State Church of the Roman Empire.
It introduced false doctrines: - The trinity, immortal souls, heaven-going at death, eternal torment in ‘hell’, ‘just’ wars, division into clergy and laity, transubstantiation, penance, confession to ‘priests’, the Pope as the head of the Church, indulgences, etc.
The Roman Church became the ‘mother of harlots’ described in Revelation 17:5, reigning over kings in the time of the ‘Holy Roman Empire’.
The multitude of churches which arose after the ‘reformation’ and retained the false doctrines of the ‘mother Church’ became her daughters.
The Papacy is the ‘man of sin’ described in 2 Thessalonians 2:3.
God does not generally punish sins in this life.
Judgment and punishment are reserved to the day of resurrection.
John 5:28 Marvel not at this: for the hour is coming, in the which all that are in the graves shall hear his voice, 29 And shall come forth; they that have done good, unto the resurrection of life; and they that have done evil, unto the resurrection of damnation (condemnation).
The faithful will receive eternal life and the unfaithful eternal death.
Whilst we have life, we have opportunity to repent and turn our backs on sin.
The parable of the prodigal son (Luke 15) illustrates the greatness of God’s mercy.
May I suggest that you read ‘Your Share in God's Promises’ here:
I hope you find this helpful.