“Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.” Hebrews 3:12
Apostasy (Greek ~ apostasia) appears twice in the New Testament as a noun (Acts 21:21; 2 Thessalonians 2:3) and here in Hebrews 3:12 as a verb (aphistemi, translated “to depart” or “turn away”). The Greek term is defined as a falling away, defection, withdrawal, or turning from what one has formerly turned to. Therefore in this study we will seek to prove that an apostate is not an unbeliever but someone who once believed, and through personal choice has chosen to follow the Lord no longer. In doing so, we will clearly see that the teaching of eternal security as promoted by Calvinists is false and dangerous to one’s eternal life.
 To apostatize means to sever one’s saving relationship with Jesus Christ or to withdraw from vital union with and true faith in Him. In other words, personal apostasy is possible only for those who have first experienced salvation, regeneration and renewing by the Holy Spirit. “They on the rock are they, which, when they hear, receive the Word with joy; and these have no root, which for a while believe, and in time of temptation fall away.” (Luke 8:13.) Also notice what the writer of Hebrews 6:4-6 has to say upon this subject; “For it is impossible for those who were once enlightened, and having tasted of the heavenly gift, and were made partakers of the Holy Ghost, and have tasted the good Word of God, and the powers of the world to come, 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.” It is apparent that it is not a mere denial of New Testament doctrine by the unsaved spoken of here, but the rejection of Christ and the things of God by a one time believer. Apostasy may involve two separate, though related, aspects: (a) theological apostasy, i.e., rejection of all or some of the original teachings of Christ and the apostles and replacing them with liberal theology, false religion, or even atheism. Paul warns us that “The Spirit speaketh expressly, that in the latter times some shall depart from the faith, giving heed to seducing spirits, and doctrines of devils.” (1 Timothy 4:1.) He later gives the reason for this apostasy in his second letter to Timothy; “For the time will come when they will not endure sound doctrine; but after their own lusts shall heap to themselves teachers, having itching ears; and shall turn away their ears from the truth, and shall be turned unto fables.” (2 Timothy 4:3-4), and (b) moral apostasy, i.e., the former believer ceases to abide in Christ and instead becomes enslaved again to sin and immorality ~ “What then? shall we sin, because we are not under the law, but under grace? God forbid. Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness? But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you. Being then made free from sin, ye became the servants of righteousness. I speak after the manner of men because of the infirmity of your flesh: for as ye have yielded your members servants to uncleanness and to iniquity unto iniquity; even so now yield your members servants to righteousness unto holiness. For when ye were the servants of sin, ye were free from righteousness. What fruit had ye then in those things whereof ye are now ashamed? for the end of those things is death. But now being made free from sin, and become servants to God, ye have your fruit unto holiness, and the end everlasting life. For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.” (Romans 6:15-23.) Please remember that these verses were written TO BELIEVERS, and not to the unsaved. This same truth is taught in Romans 8:6-13 ~ “ For to be carnally minded is death; but to be spiritually minded is life and peace. Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be. So then they that are in the flesh cannot please God. But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his. And if Christ be in you, the body is dead because of sin; but the Spirit is life because of righteousness. But if the Spirit of him that raised up Jesus from the dead dwell in you, he that raised up Christ from the dead shall also quicken your mortal bodies by his Spirit that dwelleth in you. Therefore, brethren, we are debtors, not to the flesh, to live after the flesh. For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.” Again, notice that Paul is referring to believers, and not the unsaved. We see from the above Scriptures just how important it is to maintain our walk in Jesus Christ and not allow ourselves to be overcome by worldliness and sin.
 The Bible issues urgent warnings concerning the possibility of apostasy, designed both to alert us to the deadly peril of abandoning our union with Christ and to motivate us to persevere in faith and obedience. The divine purpose of these warning passages must not be weakened by the view that states that the warnings are real, but that in reality there is no possibility of apostasy or losing salvation. In fact we should regard them as a sincere alarm if we want to attain final salvation. The Bible is full of such warnings but the following verses should be enough to convince the child of God of the need to endure to the end. Acts 14:22 informs us that Paul exhorted the Church in Derbe to “continue in the faith, and that we must through much tribulation enter into the kingdom of God.” It is the Lord’s desire to present us, His Church, pure and holy, but this can only be achieved if we live according to His Word. Paul tells us that this is possible “if ye continue in the faith, and be not moved away from the hope of the gospel.” (Colossians 1:23.) As mentioned above, the Holy Spirit reveals to us that in the latter days people will fall away from the Lord and give themselves over to false doctrines. These doctrines damn the soul. This is why it is good to take the advice given to Timothy, “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.” (1 Timothy 4:16.) If there was no possibility of turning away from Christ why would Paul further charge Timothy to “fight the good fight of faith, lay hold on eternal life.” (1 Timothy 6:12)? It is this keeping a tight grip upon salvation that is so essential and it’s the very place that so many fail and fall. Because of the “once saved, always saved” doctrine many live ungodly lives. I have personally known Christians who lived like the world with no real desire to live for God, simply because they believed if they are saved and cannot lose salvation, then why worry! These are doing exactly what the Bible warns the early Church not to do; “How shall we escape if we neglect so great salvation; which at the first began to be spoken by the Lord, and was confirmed unto us by them that heard Him; God also bearing them witness, both with signs and wonders, and with divers miracles, and gifts of the Holy Ghost, according to His own will?” (Hebrews 2:3-4.) If the truth be told, what is really happening here is the hardening of the heart. Jehovah destroyed His own people in the wilderness because of their refusal to accept and follow His Word. Hebrews 3:8 cautions us, “Harden not your hearts, as in the day of provocation, in the day of temptation in the wilderness.” If we do we also will find that God will say unto us, “They shall not enter into my rest.” (v.11). This is the reason the very next verse warns us to “Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the Living God” (v.12). Calvinists fail to see that a Christian who backslides is a sinner and needs to be converted or else he will go to a lost eternity in Hell. This is what James points out so effectively in 5:19-20; “Brethren, if any of you do err from the truth, and one convert him; let him know, that he which converteth the sinner from the error of his way shall save a soul from death, and shall hide a multitude of sins.” Very sound advice when we consider that this was James’ last statement to his readers. To sum up this section: We need to pay attention to what the Lord has given to us if we are going to reach the goal. If we give up and turn away from the Lord, it is not that we have lost salvation but that we have thrown it away, we will not inherit eternal life. What the Lord has given to us needs to remain and we need to continue in Him. “Let that therefore abide in you, which ye have heard from the beginning. If that which ye have heard from the beginning shall remain in you, ye also shall continue in the Son, and in the Father.” (1 John 2:24.)
 At this point let us turn to some examples of apostasy in the New Testament. All will admit that it is by God’s grace that we are saved through faith in our Saviour Jesus Christ. To live contrary to the Word of God would make us fall from this grace, just as Paul pointed out to the Galatian Church ~ “Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace.” (Galatians 5:4.) This was his response to the Gentile Church in Galatia as they were becoming confused by the teachings of those who said that they must follow Jewish customs to be saved. Calvinists have told me that such passages of Scripture (including those in Hebrews) were written to Jewish converts and do not apply to Gentile believers. Firstly, despite the fact that Hebrews was written to Jewish converts to Christianity they were Christians, therefore the epistle to the Hebrews was written to Christians; Secondly, though Paul mentions the Jewish legalists, he was writing to the Gentile Church in Galatia; Lastly, the New Testament letters were written to Churches or at least individuals in Churches, and these Churches were made up of Christian believers regardless if they came from a Jewish or Gentile background ~ “There is neither Jew nor Greek [Gentile], there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.” (Galatians 3:28.)
The possibility of losing salvation sounds blasphemous to some, yet this is exactly what the Word of God teaches. If we were to reject Christ we would be making shipwreck of our faith. “Holding faith, and a good conscience; which some having put away concerning faith have made shipwreck: of whom is Hymenæus and Alexander; whom I have delivered unto Satan, that they may learn not to blaspheme.” (1 Timothy 1:19-20.) Once you have made shipwreck your faith in Christ there are no other salvation vessels provided by the Lord. The only way you can have full assurance of salvation is by maintaining a continual trust in Christ, or to put it another way, by staying in His fellowSHIP.
God makes us aware that there will be false prophets in the Church. It may be argued that these people are not real Christians, but it is obvious that they are in the Church to deceive those who are saved and to lead them astray. The apostle Peter writes, “There were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction. And many shall follow their pernicious ways.” (1 Peter 2:1.) Yet, to say that the false teachers\prophets and their followers were not once true believers flies in the face of Truth. In verses 20-22 Peter makes it abundantly clear that this is the case ~ “For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them. But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.”
If you are still unconvinced that a person can fall away, put away and reject the salvation he has received, then what do you think about Ananias and Sapphira (Acts 5:1-11)? What do you think of Demas who forsook Paul “having loved this present world” (2 Timothy 4:10)? In fact the Bible predicts that during the last days, the antichrist age, there will be a falling away from the Lord (2 Thessalonians 2:3.)
 The steps that lead to apostasy are as follows:
(a) “Follow peace with all men, and holiness, without which no man shall see the Lord.” (Hebrews 12:14.) The lack of personal holiness is the major factor in backsliding and falling away from the Lord. Almost everyone who stops following God’s way has been enticed by this world. There is a general lack of seriousness in the Church today regarding the call to commitment and holiness. It has become outdated and legalistic to some, yet it is a must if we are going to see the Lord. This desire to serve God must continue regardless of what temptations or tribulations we may face in the Christian life. The sad but true fact is there is very little substance to the gospel being presented today. Because of this there is a corresponding lack of dedication amongst believers. They fall away from Christ because they are not rooted in Him ~ “They on the rock are they, which, when they hear, receive the Word with joy; and these have no root, which for a while believe, and in time of temptation fall away.” (Luke 8:13.) This is why preachers of the Gospel need to get back to preaching the Bible and to tell their listeners that they should be “rooted and built up in Him, and stablished in the faith.” (Colossians 2:7.) Today there is too much concern about what other people think. Unless we are bold in our faith it is easy to become embarrassed about being rejected for being a Christian and to seek man’s approval. “How can ye believe, which receive honour one of another, and seek not the honour that cometh from God only?” (John 5:44.)
(b) As worldliness gets its claws into a believer’s life the joy of serving Jesus departs. There is no longer a drawing near to God and His Word. The things of God begin to take second place until they become the last thing on our mind. Listen to these instructions that were originally written to the Hebrews: “Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need. . . . Wherefore He is able also to save them to the uttermost that come unto God by Him, seeing He ever liveth to make intercession for them. . . . But without faith it is impossible to please Him: for he that cometh unto God must believe that He is, and that He is a rewarder of them that diligently seek Him.” (Hebrews 4:16; 25; 11:6.)
(c) Is it not amazing that what Christians once called sin is now tolerated as acceptable behaviour. Christians, like the world, are no longer ashamed of their sin but openly flaunt it in the guise of so-called Christian Liberty. What really happens in this case is that righteousness is no longer loved. Listen, “Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abuses of themselves with mankind, nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God.” (1 Corinthians 6:9-10.) If you happen to see your own sin in that list then you need to get right with God now before it is too late! Do you want to see a confirmation of what Paul wrote? Well let’s look at Ephesians 5:5 ~ “For this ye know, that no whoremonger, nor unclean person, nor covetous man, who is an idolater, hath any inheritance in the kingdom of Christ and of God.” My aim here is not to condemn you but to make you alert to the true facts of our responsibility in serving Jesus Christ. In fact Hebrews 3:13 gives us each such a command ~ “Exhort one another daily, while it is called Today; lest any of you be hardened through the deceitfulness of sin.”
(d) Through hardening of the heart the ways of God are rejected. Soon the still small voice of God’s Holy Spirit is drowned out with the world’s multitudes of voices offering a more enlightened, liberal way. It is then that the Holy Spirit of God is grieved and quenched in our lives. The temple He came to inhabit has been violated by sin ~ “Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?” But don’t stop there! “If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.” (1 Corinthians 3:16-17.)
 If apostasy continues its course unchecked, an individual may eventually reach the point when no second beginning is possible. Continuing to wilfully sin is so dangerous yet pastors and teachers do not warn their flocks. “For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sin, but a certain fearful looking for of judgement and fiery indignation, which shall devour the adversaries.” (Hebrews 10:26-27.) Through false teaching Christians do not believe that there is a limit to God’s patience. Hebrews 10:31 reminds us that “it is a fearful thing to fall into the hands of the Living God.” To safeguard against the danger of ultimate apostasy all we have to do is love God enough to obey all His Word. It is that easy, yet why do so many fool around and play religion? In fact they have doomed themselves to a lost eternity, and at the same time deceived themselves with the thought, “Well, at least I said the sinners prayer.” If you find yourself in this position at this moment then do something about it. “Today, if ye will hear His voice, harden not your hearts.” (Hebrews 3:7-8, :15; 4:7.) Please note that this phrase is mentioned three times within 20 verses.
 It must be made clear that while apostasy is a danger for all who drift from the faith and fall away, it is not made complete without constant and willful sinning against the voice of the Holy Spirit.
 Those who by an unbelieving heart depart from God may think they are Christians, but their indifference to the demands of Christ and the Holy Spirit and to the warnings of Scripture points otherwise. Because of the very real possibility of self-deception, Paul exhorts all those claiming salvation to “examine yourselves, whether ye be in the faith; prove your own selves.” (2 Corinthians 13:5.)
 Finally, any person who becomes sincerely concerned about his spiritual condition and finds in his heart the desire to return to God in repentance, has sure evidence he has not committed unpardonable apostasy. God wants you to live under the power of His saving faith. If Jesus did so much for you in dying on the cross to bring you to eternal life, then is it too much to ask that you live for Him the way He requires?
“I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service. And be not conformed to this world, but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.” (Romans 12:1-2.)
This full excerpt was taken from the Full Life Study Bible