More than 350 years ago Thomas Brooks penned the words, "The being in a state of grace makes a man's condition happy, safe, and sure; but the seeing, the knowing of himself to be in such a state, is that which renders his life sweet and comfortable." Such an assertion is as true today as it was then, since the assurance of one's salvation is an issue that individual Christians have wrestled with in virtually every generation since the inception of the church. Surely this is due to the fact that believers, who have taken the Scriptures seriously, have been confronted with passages that offer assurance of eternal life as well as those that bid them to test themselves or even warn them of the perils of falling away. After querying such texts, many ponder whether they can truly be assured that they have been born of God (2:29; 3:1-2,9; 4:4,7; 5:1,4,18) and whether this divine birth will result in final salvation whereby the believer will have eternal life (5:13). In light of this, it is clear that this book grapples with a biblical, theological issue that is of utmost importance for every child of God.
No other book of the New Testament speaks of the believer's confidence or assurance of salvation as frequently and explicitly as the first letter of John, for the predominant theme of the entire letter is Christian certainty. This is seen in the way the writer assures his readers that the cross-work of Christ is the effective solution for their sins (1:5-2:2; 4:9-10), the way he reassures them of their present status with God (2:3-6,12-14; 3:1-2; 4:4; 5:18-20), as well as his numerous "tests of life," given to help them "know" that they have come to know God (2:3). This letter, however, also contains warnings regarding false teaching and exhortations to persevere in love, righteousness, and the message heard from the beginning (2:15,24,26-28; 3:7; 4:1; 5:21). Thus, its readers are confronted with the tension between various assurances regarding their present status as children of God and passages that bid them to test themselves, exhort them to live righteously, and warn them of false teaching. To be sure, the very question of assurance of eternal life in 1 John centers on the relationship between such passages. Therefore, this study will seek to answer the question, What is the nature of the believer's assurance of eternal life in the first letter of John?
I will argue that the writer of 1 John grounds his reader's assurance of eternal life on the solid foundation of the person and work of Jesus Christ (1:1-2:2; 4:9-10; 5:18). Jesus is clearly displayed as the believer's παράκληος ("advocate") with the Father (2:1) and the ἱλασμός ("propitiation") of their sins (2:2; 4:10). Given that sin is inevitable in the life of the believer (1:7-2:2; 5:16-17), nothing other than the work of Christ can be viewed as the foundation of assurance, for it is the only effective remedy for their sins and thus the only ground for confidence of right standing with God. Moreover, it will be argued that assurance is not only grounded in the past work of Jesus on the cross but also on the promise of His ongoing work of protecting those who have been born of God (5:18).
While assurance is fundamentally grounded in the work of Christ, this letter also demonstrates that the lifestyle of the believer serves as a vital corroborating support for such assurance. This is seen in the numerous sets of criteria or "tests" that occur throughout the letter. Here I will argue that John viewed his readers as a new covenant community, expecting God's own Spirit to dwell in them and empower them to walk in the light. The Holy Spirit should produce a change of life in the new covenant believer that is observable in the public arena and therefore able to be tested and validated. John's tests were written with the primary purpose of his readers' introspection and subsequent reassurance as they came to understand that it was they who were holding to a right belief in Jesus, striving to live righteously, and loving the brethren. Moreover, I will also argue that these tests have a retrospective aspect in that they enabled John's readers to comprehend that those who departed from the fellowship had done so because they were never genuinely part of the community, as made obvious by their fundamental failure of each of the three tests. Finally, I will argue that the tests at least implicitly have a prospective or exhortative element. In other words, even though the primary purpose of a statement like "no one born of God sins" (3:9) was to distinguish between those who are indifferent to sin and those who strive to live righteously, such a passage would nevertheless serve to motivate a child of God to continue to strive to live without sin.
This prospective element of the tests as well as John's periodic warnings about the false teachers and exhortations to persevere (2:15a,24,26-28; 3:7; 4:1; 5:21) give rise to the discussion on perseverance in 1 John and its relationship to assurance. Here I will argue that those who have truly been born of God will take John's warnings and admonitions seriously and therefore persevere in holy living. Those who fail to do so demonstrate that they have never truly been born of God (2:19). Therefore, this study will argue that John views the believer's assurance of eternal life as compatible with his ongoing need to persevere in righteous living. In fact, it will be argued that these two are inextricably tied together in that the believers' confidence that they are children of God due to the work of Christ is a key impetus to their perseverance (3:3; 4:11) and their perseverance in righteous living actually aids in bolstering their assurance (2:3-5).
Nevertheless, while John emphasizes that his readers' perseverance in righteousness is vital, it cannot be viewed as the ground of their assurance. This is clearly found in the work of Christ. Therefore, the thesis of this study is that the letter of 1 John teaches that assurance of eternal life is fundamentally grounded in the work of Christ and supported in a vital yet subsidiary way by the lifestyle of the believer. One's lifestyle is "vital" in that if a person fails to keep the commands, love the brethren, and have a right confession of Jesus, he demonstrates that he was never a child of God and should have any false assurance eradicated. It is "subsidiary" in that the letter also teaches that no one lives perfectly holy (1:6-2:2; 5:16-17), so the believer must continually look back to the work of Christ on the cross for the forgiveness and cleansing of sin.
Such a thesis lands us right in the middle of the historical debate on the nature of the believer's assurance, where one of the central concerns from the Reformation onward has been the outworking of the biblical tension of finding one's assurance in Christ and the relation of that assurance to persevering in godly living. Since the inception of the doctrine of assurance, this tension has been the source of much dispute over such issues as the degree to which the believer's assurance is linked to his perseverance in godly behavior. Of course there is also the question of how much assurance a believer might have without being presumptuous. In other words, can a believer be assured of final salvation, or is he only able to find assurance that he is trusting in Christ today? These and similar questions have been debated since at least the time of the Reformation and continue into the present day. Therefore, in order to move forward properly with this present examination of assurance in 1 John, it is helpful first to look back at some of the history of this debate.