Can a believer lose his or her salvation? That is a question that troubles a lot of Christians, the answer can give great peace and stability to a true child of God.
We need to understand that the word of God teaches that God alone can provide salvation. Man has no part to play in his salvation, it is all of God. Only a Divine human Savior could go to the cross and pay the price of sin and only God by His Spirit could apply that salvation to an individual. The scripture says that we are saved by grace through faith. Grace is God providing salvation, faith moves the hand of God to provide it. Salvation is the gift of God (John 3:16), once the gift has been received only the giver can take it away and He has promised never to do that, Psalm 37:28 John 6:37 Romans 8:38,39.
God has promised that salvation is forever and He cannot lie or break His promise, John 5:24 John 6 :47. You can't have everlasting life for a few years and then lose it, once you have it you have it is forever, John 6:40, in this case the outcome rests entirely on God and His promise.
We need to understand also what happens at salvation, Peter said that when a person is saved he or she becomes a partaker of the divine nature (2 Peter 1:4). We actually become a partaker of the very nature of God, we are born again. Paul said we become new creatures in Christ. John said that our new nature cannot sin (1 John 5:18) though we know that the old nature is ever present until we are glorified, yet we have a divine nature that cannot sin. This new nature, a divine nature that cannot sin could not turn away from the Lord, it can never go back, it could never reject what it has already received, it can never be lost. If a true believer were to be cast into hell God would be cast into hell with him, Hebrews 13:5. Other verses that give assurance of a salvation that can never be lost, John 10:26-29 Matthew 24:35 Romans 8:16
We need to understand that many people think they are saved and they are not. False profession is a major problem in this issue. We see this in Matthew 13:20-22, we see the gospel being spread as a farmer sows the seed some respond and make a profession of faith and they look good for a while but time proves that they never had the root of the matter, they had never been saved, Verse 6, "they had no root".
We see this also revealed in Matthew 7:21-23, notice they were self deceived into believing that they were saved and they were not. It's not that they had been saved and lost their salvation, Jesus said to them, "I never knew you", they were deceived into thinking they were believers but they were never saved.
That is the curse of New Evangelicalism that plagues the evangelical church today, they preach easy-believism, you don't need to repent, you don't need to change, look at us we are so much like the world you can hardly tell the difference, just name the name of Jesus and you are in. The end result is a disaster, the disaster of Matthew 7:21-23. A church full of pseudo believers is a catastrophe. Jesus said, "....Except ye repent, ye shall all likewise perish", Luke 13:3,5.
Paul said, "Examine yourselves, whether ye be in the faith...." 2 Cor. 13:5. We need not be in doubt, 1 John 5:13 "These things have I written unto you that believe on the name of the Son of God; that ye may KNOW that ye have eternal life...."
It's not saved and lost, it's lost because they were never really saved in the first place. 2 Tim. 2:19
MARKS OF A GENUINE CHRISTIAN
These things do not help you to obtain salvation (with the exception of numbers 1 & 2) but are the evidence that salvation has taken place.
1-A true understanding of who Christ is and what He has done.
2-A recognition of our sin and rebellion against God a which is accompanied by repentance and faith in Christ as your savior.
3-An obedience to the words and commands of Christ which is accompanied by a hunger to know God's word. 1 John 2:3,4 ! John 3:24 John 14:21 Jeremiah 15;16
4-Love for our brothers in Christ. I John 2:9-11 1 John 3:14 john 13:35
5-Fellowship with other Christians. 1 John 1:3 Hebrews 10;25 Acts 2:42,46,47
6-Prayer - a genuine relationship with Christ will involve communication with Him. John 15:7 John 16:24
7-Witnessing - A readiness to witness to others as to what Christ has done for you. Mark 16:15 Acts 1:8
8-Baptism - Baptism by immersion is not an option for a true believer. Though it has no part in salvation, it is a command of Christ. Matthew 28:19 Acts 2:37-38
These are the eight marks of true salvation, if your faith in Christ is genuine saving faith, these marks will be found in your life in the coming days. 2 Corinthians 5:17