Recently, a friend was invited by fellow Christians to discuss her belief in the doctrine of perseverance of the saints. Some of those attending are not persuaded. How would you prepare for such a discussion? Here’s some of what I shared with her. I hope you find it helpful.
Reformed Christians have long recognized a certain unhappy logic to the belief that one can lose salvation. If some whom the Spirit regenerated are later damned, it would mean salvation rests decisively upon one’s will, even if only to continue believing. In this case, the basic difference between those who persevere unto eternal life and others who don't would not be God’s grace given freely in Jesus Christ—both groups having received the same Spirit—but that the former were more willingness to continue cooperate. Remember, however, this ability to will faith is not itself morally neutral. Belief in Christ is absolutely good and right.
Reformed believers understand this perseverance in faith to be a gift of God imparted by the Spirit, part of the “first fruits” of sanctification. By contrast, those who think salvation can and sometimes is forfeited by genuine believers imply that faith’s decisive fortitude must be found within, and it makes all the difference in who is saved and lost. Therefore, if not explicitly teaching salvation by good works, any system of doctrine which denies perseverance fundamentally degrades the Gospel into salvation by good will, which is essentially the same thing. It’s a subtle shift away from faith in Christ alone to faith at least partly in ourselves.
Where to Begin?
The best resources are probably right at your fingertips. Namely, I recommend you carefully read the Canons of Dort (official URC version). They were written to address this very issue. In particular, the Fifth Head of Doctrine (p. 278 in the version linked above) concerns Perseverance of the Saints. The entire Canons are worth studying in detail and are probably better than most books and articles in terms of compact clarity.
Bible Verses on Perseverance
Here's a site called Five Solas that lists all the Scripture references one could hope for, such as, "he who began a good work in you will complete it to the day of Christ Jesus," and, "they went out from us in order that it might be manifest that they were not of us, for had they been of us, they most certainly would have continued with us."
Now, most importantly, let's pray together for God to grant grace both to you and them, to have opened hearts and winsome character. After all, our goal is to comfort one another with the sure mercies of Jesus. Grace to it! I'll pray for you even now. Let me know how things go or if you have additional questions.