Apostates are a very distressing issue for many Christians. How does it reconcile with the doctrine of eternal security? If they can lose their salvation, could I lose mine? And what if they're right? If they could be convinced that Christianity is true, only to later be convinced it isn't, what are the implications for the Christian faith?
God alone knows the heart, but lucky for us, God has written to us. In this, He has described many things about the heart, including what is in the hearts of the apostate. Eternal security is solidified in scripture, for we are repeatedly told that the Holy Spirit seals us, and is given to us as a guarantee of salvation (2 Corinthians 1:22; Ephesians 1:13; Ephesians 4:30). We are told we can know we have eternal life (1 John 5:13), and that no one, not even we, are strong enough to take us out of Christ's hands (John 10:28-29).
But this, of course, does not answer the issue of apostates. They believed, and so were they not saved? And yet they left, so did they not lose that salvation? For this, we need to understand exactly what faith is. When people think of faith, they often think of mere intellectual assent. "Sure, I believe in Jesus". Ok, but as James points out, so does the devil (James 2:19). So do heretics. So do many unbelievers. There are people out there right now who will actually admit they believe in God, and yet they will not worship Him, simply because they hate Him. And though atheists will not often admit they believe in God, many of them hold to that same philosophy: "If I believed, I would still rebel". None of these have the kind of faith that saves.
And so let us turn to the words of Paul, in Hebrews 10. From verse 32, up until 39, we read "But recall the former days in which, after you were illuminated, you endured a great struggle with sufferings: partly while you were made a spectacle both by reproaches and tribulations, and partly while you became companions of those who were so treated; for you had compassion on me in my chains, and joyfully accepted the plundering of your goods, knowing that you have a better and an enduring possession for yourselves in heaven. Therefore do not cast away your confidence, which has great reward. For you have need of endurance, so that after you have done the will of God, you may receive the promise: “For yet a little while, and He who is coming will come and will not tarry. Now the just shall live by faith; but if anyone draws back, My soul has no pleasure in him.” But we are not of those who draw back to perdition, but of those who believe to the saving of the soul."
Emphasis on verse 39: But we are not of those who draw back to perdition, but of those who believe to the saving of the soul. The distinction is made here between intellectual assent and saving faith. Intellectual assent may falter, changing on any given day. One day, my faith is strong. I see a mountain of evidence, and not even a mole hill for any other worldview. The next day, I come across a question I cannot answer, and it plants a seed of doubt. Then perhaps, as time goes on, that seed is choked out, even assuming it begins to take root. This kind of faith is fickle.
But then we have saving faith. The kind that cannot falter. The kind that the Spirit Himself brings, as He testifies with our spirit that we are children of God (Romans 8:16). Can such faith perish from our hearts? My brethren, I believe most, if not all of you can resonate with me when I say I would sooner doubt that I am my mother's son than that the Lord Jesus Christ has bought for me an eternal inheritance in His Kingdom.
And so what of apostates? Well put simply, they never had this kind of faith. They did not lose salvation because they never had salvation. They did not leave us, because they were never of us, and as the Apostle John tells us from the Lord, "they went out from us that they might be made manifest that none of them were of us". Allow me to repeat, that they might be made manifest that none of them were of us.
In Christianity, there is no such thing as a true apostate. An apostate joins the Church under false pretences. Not necessarily out of malice (although just like Judas, such is certainly within the realm of possibility), but nevertheless, those who convert are not necessarily truly converted. This, we see from the parable of the sower in Matthew 13. The Gospel can be preached to many people, but it may fall on ground that is not fit to receive it. Some people, the faithful, are fertile ground. We receive the word with all readiness, and when our faith is planted, its roots grow deep, and it produces much fruit. But there is other ground. There is the ground of the wayside, where the seed does not plant, but is eaten by birds. There is the rocky ground, from which the seed grows, but it springs from the ground and is burned by the sun, as it has no roots. There is the thorny ground, with hostile plants to choke out the seed.
And Jesus proceeds to explain the parable of the sower, telling us what every ground represents. "When anyone hears the word of the kingdom, and does not understand it, then the wicked one comes and snatches away what was sown in his heart. This is he who received seed by the wayside. But he who received the seed on stony places, this is he who hears the word and immediately receives it with joy; yet he has no root in himself, but endures only for a while. For when tribulation or persecution arises because of the word, immediately he stumbles. Now he who received seed among the thorns is he who hears the word, and the cares of this world and the deceitfulness of riches choke the word, and he becomes unfruitful. But he who received seed on the good ground is he who hears the word and understands it, who indeed bears fruit and produces: some a hundredfold, some sixty, some thirty." (Matthew 13:19-23).
And so which ground is the apostate? In truth, it's hard to say. God alone knows for sure. Perhaps an apostate is he who hears the word, yet does not understand it. This is probably the most common, as in my experience, even those who claimed they were Christians for a decade or more often show less knowledge of the word than those who never claimed faith in the first place. I can honestly say I have never met an exception.
Or perhaps they were the stony ground. They heard it, received it with joy, yet had no root, and so fled when persecution arose. False converts are certainly not the best of martyrs. Of course, some still compromise. One need only look at Theistic Evolutionists, or those who shield false religions like Islam from honest criticism, or those who deny the existence of Hell. Though they push serious heresies, they still seem to hold some degree of faith under the heat of persecution. A weak root is a root nonetheless, and Jesus said faith the size of a mustard seed can move mountains. But persecution, nevertheless, dissuades false converts, forcing them to apostatise.
Maybe an apostate is the thorny ground. The word is choked not by persecution, but by worldly things, such as riches. I remember once hearing of a pastor who likely falls under this category. For some unfathomable reason (although given his apostasy, totally understandable), he decided to live as an atheist for a whole year, decided he liked it, and of course left the Church. This shows us that not even a pastor is truly safe from false faith.
So we see it is not always clear why someone might apostatise. Some join the Church out of malice, others out of ignorance, and they leave for the same reason. They were not of us, and so they went out from us, that it might be made manifest that they were never of us. But my brethren, God knows this. Is the God who tells the end from the beginning surprised when a man turns from Christ? Did the God who knows the heart of men not know the motives of that heart when the sinner professed faith for the first time? God knows the heart; who is what kind of ground. And thus, He writes the correct names in the Book of Life every time, and He never once uses an eraser.
And now for some self examination for us all. See, most of us know what sort of ground we are. I personally have experienced every trial in the parable. I have had times when I did not understand the word, and yet the birds did not steal my seeds. I have suffered trials and persecution for my faith, and yet I have not been burned, for my root is too deep. I have been tempted by the world, both by its pleasures and its riches, and yet no thorn to this day has been able to choke out my roots. Can you relate? My brethren, who among you has not experienced these things? If you have not, I promise, you will, for every man, woman, and child is on Satan's hit list. And for sake of your own growth, God will not restrain him completely. You will face trials. Trials that would make a false believer apostatise, not because there is something wrong with the Christian faith, but because there is something wrong with the apostates. They do not understand the word, or they do not like the attacks that come upon the word, or they simply do not like the reward of the word while on Earth.
But if your faith is true, you are fertile ground. You will be able to echo the words of Paul: "I am not of those who draw back to perdition, but of those who believe, to the saving of the soul". You will endure to the end, you will leave this perishing world behind, and when the Book of Life is open, Christ will call your name, and you will enter the Kingdom of Heaven as a child of God, where you will live forever. The only question you need to ask is what sort of fruit will you produce? Will you bear thirty fold, sixty fold, a hundred fold? God alone can judge. But if your faith is true, it will be too deeply rooted, and your ground will be fertile, and you will not be cast into the fire. Take heart, my brethren, for even when the foretold "great apostasy" occurs, you yourself will be saved.