Answer: Perseverance of the Saints is the name that is used to summarize what the Bible teaches about the eternal security of the believer. It answers the question: Once a person is saved, can they lose their salvation? Perseverance of the saints is the P in the acronym TULIP, which is commonly used to enumerate what are known as the five points of Calvinism. Because the name perseverance of the saints can cause people to have the wrong idea about what is meant, some people prefer to use terms like: “Preservation of the Saints,” “Eternal Security,” or “Held by God.” Each of these terms reveals some aspect of what the Bible teaches about the security of the believer. However like any biblical doctrine what is important is not the name assigned to the doctrine but how accurately it summarizes what the Bible teaches about that subject. No matter which name you use to refer to this important doctrine a thorough study of the Bible will reveal that when it is properly understood it is an accurate description of what the Bible teaches.
The simplest explanation of this doctrine is the saying: “Once saved, always saved.” The Bible teaches that those who are born-again will continue trusting in Christ forever. God, by His own power through the indwelling presence of the Holy Spirit, keeps or preserves the believer forever. This wonderful truth is seen in Ephesians 1:13-14 where we see that believers are “sealed with the Holy Spirit of promise, who is the guarantee of our inheritance until the redemption of the purchase possession, to the praise of His glory.” When we are born again, we receive the promised indwelling presence of the Holy Spirit that is God’s guarantee that He who began a good work in us will complete it (Philippians 1:6). In order for us to lose our salvation after receiving the promised Holy Spirit, God would have to break His promise or renege on His “guarantee,” which He cannot do. Therefore the believer is eternally secure because God is eternally faithful.
The understanding of this doctrine really comes from understanding the unique and special love that God has for His children. Romans 8:28-39 tells us that 1) no one can bring a charge against God’s elect; 2) nothing can separate the elect from the love of Christ; 3) God makes everything work together for the good of the elect; and 4) all whom God saves will be glorified. God loves His children (the elect) so much that nothing can separate them from Him. Of course this same truth is seen in many other passages of Scripture as well. In John 10:27-30 Jesus says: “My sheep hear My voice, and I know them, and they follow Me; and I give eternal life to them, and they will never perish; and no one will snatch them out of My hand. My Father, who has given them to Me, is greater than all; and no one is able to snatch them out of the Father’s hand. I and the Father are one.” Again in John 6:37-47 we see Jesus stating that everyone that the Father gives to the Son will come to Him and He will raise all of them up at the last day.
Another evidence from Scripture of eternal security of a believer is found in verses like John 5:24 where Jesus says: “Truly, truly, I say to you, he who hears My word, and believes Him who sent Me, has eternal life, and does not come into judgment, but has passed out of death into life.” Notice that eternal life is not something we get in the future but is something that we have once we believe. By its very nature eternal life must last forever or it could not be eternal. This passage says that if we believe the Gospel we have eternal life and will not come into judgment, therefore it can be said we are eternally secure.
There is really very little scriptural basis that can be used to argue against the eternal security of the believer. While there are a few verses that, if not considered in their context, might give the impression that one could “fall from grace” or lose their salvation, when these verses are carefully considered in context it is clear that is not the case. Many people know someone who at one time expressed faith in Christ and who might have appeared to be a genuine Christian who later departed from the faith and now wants to have nothing to do with Christ or His church. These people might even deny the very existence of God. For those that do not want to accept what the Bible says about the security of the believer these types of people are proof that the doctrine of eternal security cannot be right. However, the Bible indicates otherwise and it teaches that people such as those who profess Christ as Savior at one time only to later walk away and deny Christ, were never truly saved in the first place. For example 1 John 2:19 says, “They went out from us, but they were not of us; for if they had been of us, they would have remained with us; but they went out from us, in order that it might be made manifest that they all are not truly of us.” The Bible is also clear that not everyone who professes to be a Christian truly is. Jesus Himself says that not everyone who says “Lord, Lord” will enter the kingdom of heaven (Matthew 7:21-22). Rather than proving we can lose our salvation, those people who profess Christ and fall away simply reinforces the importance of testing our salvation to make sure we are in the faith (2 Corinthians 13:5) and making our calling and election sure by continually examining our lives to make sure we are growing in godliness (2 Peter 1:10).
One of the misconceptions about the doctrine of the perseverance of the saints is that it will lead to “carnal Christians” who believe that since they are eternally secure they can live whatever licentious lifestyle they wish and still be saved. But that is a misunderstanding of the doctrine and what the Bible teaches. A person who believes they can live any way they want because they have professed Christ is not demonstrating true saving faith (1 John 2:3-4). Our eternal security rests on the biblical teaching that those whom God justifies, He will also glorify (Romans 8:29-30). Those who are saved will indeed be conformed to the image of Christ through the process of sanctification (1 Corinthians 6:11). When a person is saved, the Holy Spirit breaks the bondage of sin and gives the believer a new heart and a desire to seek holiness. Therefore a true Christian will desire to be obedient to God and will be convicted by the Holy Spirit when they sin. They will never “live any way they want” because such behavior is impossible for someone who has been given a new nature (2 Corinthians 5:17).
Clearly the doctrine of the perseverance of the saints does accurately represent what the Bible teaches on this important subject. If someone is truly saved, they have been made alive by the Holy Spirit and have a new heart with new desires. There is no way that one that has been “born again” can later be unborn. Because of His unique love for His children, God will keep all of His children safe from harm and Jesus has promised that He would lose none of His sheep. The doctrine of the perseverance of the saints recognizes that true Christians will always persevere and are eternally secure because God keeps them that way. It is based on the fact that Jesus, the “author and perfecter of faith” (Hebrews 12:2), is able to completely save those that the Father has given Him (Hebrews 7:25) and to keep them saved through all eternity.
The above was taken directly from the GotQuestions Web site and is a good summary of the teaching. It is not intended to be judgmental, argumentative, or to persuade anyone of anything. Persuasion of scriptural truth is always a work of the Holy Spirit.