Q. What’s the difference between eternal security,or OSAS (once saved, always saved), and perseverance of the saints (PoS)? Aren’t they the same thing?
A. Well, they are often taken to be the same doctrine, but they shouldn’t be. I admit that some people use the terms interchangeably. But I think we should be more precise and distinguish between them. For example, here are five differences that I see between PoS and OSAS.
First, the doctrine of PoS is part of Calvinism, while OSAS is not (at least, not necessarily). Many OSAS advocates reject Calvinism, such as Baptist Traditionalists and those who hold to Free Grace theology.
Second, PoS and OSAS have different foundations. PoS is founded on the Calvinist doctrine of unconditional election. God predestines some individuals to eternal salvation, and the elect are guaranteed to persevere because God chose them to be saved. By contrast, OSAS is not based on any doctrine of election, but on Jesus’ promise of everlasting life. Jesus promised what whoever believes in Him has everlasting life, shall not perish, shall not hunger, shall not thirst, shall not be cast out, shall not come into judgment, etc. (John 3:16, 36; 5:24; 6:35, 37). In short, believers are eternally secure. (See my book Chosen to Serve for a defense of the idea that election is to service, not to eternal life.)
Third, PoS and OSAS have different views of the condition of salvation. This comes out clearly when PoS advocates say that people who fall away into error or unbelief never truly believed to begin with. In effect, PoS advocates typically teach that you are born again or justified by a continuous faith that must be the “gift” faith that God only gives to the elect. Essentially, salvation does not only depend on what you believe, but how you believe it. By contrast, OSAS says there is only one kind of faith (persuasion that something is true) and that what matters is what you believe, not how you believe. Salvation requires a single act of faith in Jesus for eternal life (John 3:16, 36; 5:24; 6:47).
Fourth, PoS and OSAS take different perspectives on sanctification. According to PoS, sanctification is unconditional. Since the elect are predestined to salvation, and God causes them to be sanctified, they will never fall into major sin or unbelief in this life but will persevere in faith and good works until death. By contrast, OSAS sees sanctification as conditional. You have to choose to be a doer of the word to be sanctified, and there is no guarantee that you will progress from a carnal state to a spiritual one. But believers are eternally secure whether they experience practical sanctification or not.
Fifth, PoS and OSAS have different effects on assurance. Under PoS, you cannot be sure of your salvation because you cannot be sure if you are one of the elect with special gift faith who will persevere in faith and good works until death. By contrast, for OSAS, assurance is not only possible, it is the essence of saving faith. Jesus promised believers everlasting life. Hence, you cannot believe that promise without believing the life He gives is everlasting.