The apostle describes seven solid evidences of the work of salvation in the true believer (different from the ‘marks of grace’ usually described). All provide either strong assurance, or a profound challenge in the case of those who have not yet experienced conversion to Christ.
God has given us in the epistles of John letters full of fatherly affection for the people of God, and overflowing with guardian care towards the saints in their common struggle for the faith. He provides us with clear doctrinal instruction, but never in an emotionally detached way, and John’s deep love for the people of God comes across clearly, forming an essential part of the message of these brief letters. John writes as the last survivor of the apostles, between AD 90 and 95. He calls himself John the elder or the old man, and he feels his responsibility.
Even to refer to 1 John as a letter may give the impression that it contains some personal communication from John to his readers like other New Testament epistles, but it has no greeting, it conveys no news, it makes no reference to any named individual, it mentions no place or event, but simply contains divine truth set out in logical form. Certainly the readers are known to the apostle and he is known to them, but what he has sent them is nearer to a theological treatise. However that description would also be misleading for John writes with a sense of the immense value of God’s children, and with strong personal concern that goes far beyond any formal theological writing.
Throughout he is gentle and fatherly towards believers, but is implacable and unyielding in his opposition to error (most notably Gnosticism, which denied Christ’s humanity), and fights against it with resolute firmness knowing that the souls of God’s people are at stake.
John writes in a style closer to that of his Lord than any other penmen of Scripture. The first epistle is heavenly in character, beginning abruptly, and dealing with sublime and lofty subjects from the start, with no introduction to allow the reader to adjust. It is difficult to divide up the letter into clearly defined sections. Some have described it as having a spiral structure, that is, it returns to the same subject several times, climbing higher at each turn. John introduces a subject and then leaves it again to consider something else, before returning to it so that he can develop it further. It is characteristic of his style that he repeats himself and adds further teaching each time he revisits his subject; the same approach is seen in the Book of Revelation.
In John’s second epistle, the apostle of love is here compelled to write on a very negative theme to a godly lady. His closing words show why he finds it necessary to warn: because in his faithfulness he feels under obligation to protect the Church of Christ and all its members so that they continue in the undiminished joy which the Spirit of God desires us to have.
In his third epistle John is (remarkably) in his 90s. He is the last remaining apostle, the only one still living. He is probably at Ephesus where he appears to have been stationed in his final days, and he is writing to Gaius who belonged to a church probably not very far away, within 50 miles or so.