Apostasy is Assurance of Salvation.
One big question within Christianity is: How can we know that we are saved? Various proposals to answer this question have been put forward, but one of the most problematic that I have seen, usually championed within Calvinist or Reformed settings, is that of eternal security. This view states that, once you have been truly saved and truly regenerated in Christ, you cannot fall away from the faith. You are not saved by anything you have done, so you cannot fall away from anything that you do. It sounds nice on its face, but once you really dive into the topic it becomes very difficult to hold to. It is problematic logically, historically, and scripturally. I will get into some of the objections, but this post will be more of a general overview of the topic.
If we address the system to which this view belongs, we see problems emerging very quickly. One of the beliefs is that God has chosen you for salvation from the beginning of time, you were saved, and will always be saved. A true Christian cannot turn away from the faith. This causes confusion, as we have all seen Christians, including some prolific pastors, turn away from the faith. The response is that these people were never truly regenerated, never truly renewed by Christ, despite the fact that they were professing Christians for years, decades in some cases.
Okay, fine. That makes sense within the system itself. But it poses a truly difficult challenge to the idea of eternal security. Eternal security is meant to show you that, as a Christian, your salvation is secure. But in reality, it shows the opposite. Your faith is NOT secure, and neither is your salvation. If we take eternal security seriously, then we must also take seriously the idea that there are those who, though seemingly Christian now, in reality were never Christian and were not chosen for salvation. You may think of yourself as a Christian now, but you cannot say with any certainty that you will not turn away from the faith in the future. You may revoke Christ on your deathbed, meaning you were never truly a Christian. You may turn away from him two, three, four decades from now, meaning you never were a Christian. You might think you are now, but you have no way of knowing what the future holds, so no possible way of knowing if you are one of Gods elect here and now. Under this view, you have no true knowledge as to the state of your salvation, because it was decided by God, without your knowledge or approval, and you cannot know if you are saved until the moment you die and enter into your eternal reward or punishment.
On the other side of the coin, we have the traditional view, which is that there are those who will fall away from the faith, which is known as apostasy. Apostasy, on its surface, may seem like a bleak idea, since it could be possible for anyone to lose their salvation. But in reality, it is a system that lets us know we are truly saved.
No one becomes an apostate by accident. You cannot just accidentally say the wrong thing and suddenly lose your salvation. It must be a direct, intentional act of turning away from the faith. Because if this, you can know whether or not you are saved and are a Christian. Did you purposefully turn from the faith? No? Well, then that means you are currently saved and a true follower of Christ. It is as simple as that.
There’s so much more on this topic I could go into, but I wanted to keep it brief. There are those who fall away, and those who remain. If you remain in Christ, you can have assurance of your salvation. You might not know what the future hold, but you will know that it is a choice, moment by moment, day by day, to remain in Christ and have him remain in you.