I’ve been using commentaries since I started at Dallas Seminary forty-two years ago. I’ve found this near–universal understanding of NT commentators regarding the NT Epistles: The epistles to churches are written to warn believers that if they fail to persevere, they will be eternally condemned.
That is true of both Calvinist and Arminian commentators.
Calvinist commentators say that the letters to churches are written to a mixed audience of true and false professors. The epistles warn the readers that if they fail to persevere, then they prove they were not born again in the first place.
There’s also a newer type of Calvinist. They say that believers have initial salvation and that if they persevere, then they will win final salvation. See Schreiner and Caneday, The Race Set Before Us, as an example.
Arminian commentators believe that everlasting life can be lost by falling away. So, they see the letters as warning true believers that if they fall away and stay out of fellowship with God, then they will be eternally condemned.
I’ve been talking about commentators. However, pastors, missionaries, parachurch workers, and Bible study teachers typically have the same view of the spiritual condition of the readers of the Epistles.
I learned a different view from some of my seminary professors, including Zane Hodges, Tom Constable, Elliott Johnson, Charles Ryrie, and Howard Hendricks. They believed that the NT letters to churches were written to people who were all eternally secure. They understood the warnings in the letters to be warning the readers of judgment in this life and loss of rewards at the Judgment Seat of Christ.
I’ll give you an example of the difference in approach. Let’s consider Heb 6:4-8.
In her commentary on Hebrews, Lea Thomas comments:
This writer feels that the author of Hebrews addressed his words to those who profess to be Christians and urges them to show their genuine profession by their refusal to apostatize. The writer spoke to the readers as Christians. He could not clearly evaluate their inward condition. If the readers turned from Christ to Judaism, they would show their profession of faith in Christ had been false. Not all his readers were alike. It would be possible for some of the readers to have true professions and for some to have had false professions. The writer of Hebrews spoke to all of them as if they were true Christians, not wanting to make the judgment himself. He urged them to show their real faith by endurance in their commitment.
Some professing believers seemed to be toying with the idea of a return to Judaism. The writer of Hebrews assumed that continuance in commitment to Christ demonstrated real Christianity. The readers had professed some experiences with Christ. If they turned away from him after this initial start, their desertion would show that they were not real Christians. They needed to understand the seriousness of what they were considering (Hebrews, James, p. 110).
Contrast that with the comments on the same verses by Zane Hodges:
Naturally the words “fall away” cannot refer to the loss of eternal life which, as the Gospel of John makes perfectly clear, is the inalienable possession of those who trust Christ for it. But the writer evidently has in mind defection from the faith, that is, apostasy, withdrawal from their Christian profession (cf. Heb. 3:6, 14; 10:23–25, 35–39). The assertion that such a failure is not possible for a regenerate person is a theological proposition which is not supported by the New Testament. Paul knew the dangers of false doctrine to a Christian’s faith and spoke of a certain Hymenaeus and Philetus who said “that the resurrection has already taken place, and they destroy the faith of some” (2 Tim. 2:17–18). The author of Hebrews was a solid realist who took assaults against the faith of his readers with great seriousness (“Hebrews” in The Bible Knowledge Commentary, p. 795).
Hodges went on to say that the consequence for falling away is temporal judgment and loss of rewards at the Judgment Seat of Christ.
I should mention, before I close, that nearly all commentators who believe in eternal security understand the NT letters to individuals to be directed at individuals who were eternally secure. That includes Timothy, Titus, Philemon, and Gaius (3 John). But letters to churches are widely understood to include warnings regarding eternal condemnation.
I urge you to study this issue for yourself. Be a Berean (Acts 17:11). See what the Scriptures teach. Your own assurance of salvation is at stake. If you take the traditional view, then you can’t be sure of your eternal destiny since you can’t be sure that you will persevere (e.g., 1 Cor 9:27). But if you take the Free Grace view, then you can remain certain that you are eternally secure since nothing you do or fail to do can undo the new birth! That’s truly good news.
Keep grace in focus.