The writer of this Epistle was the beloved Apostle, John, a fisherman from Kahpehrnah-oúm and the brother of James, the son of Zebedee. He was the youngest disciple, who later owned his own house in Jerusalem (John 19:27) and was an eye witness to Jesus. He also wrote the Gospel bearing his name, two other Epistles also bearing his name, and Revelation. Only Paul wrote more New Testament Books than John, but Luke wrote greater volume than both.
The purpose of the Gospel (20:31), that humans commit trust in Christ in order to possess eternal absolute life, is complemented by the purpose of the Epistle (5:13), that those committing trust in Christ know they possess eternal absolute life. Numerous vocabulary words repeatedly used in this Epistle can also be found repeatedly in John's Gospel. One only needs to read each Book side by side to notice the similarity of style and recognize both are written by the same one.
Since there is no indication of the writer in the text, Internal evidence to John's authorship is dependent upon the accepted title that bears his name which was placed at ‘the head of the scroll' of the circulated copies; the comparison of the opening statements in his Gospel (1:1-4) with this Epistle (1:1); and a comparison of purpose, of vocabulary and of style of each. The purpose of the Gospel (20:31), that humans commit trust in Christ in order to possess eternal absolute life, is complemented by the purpose of the Epistle (5:13), that those committing trust in Christ know they possess eternal absolute life. Numerous vocabulary words repeatedly used in this Epistle can also be found repeatedly in John' s Gospel. One only needs to read each Book side by side to notice the similarity of style and recognize both are written by the same one.
External evidence comes from the Muratorian Canon (A.D. 160-200): ‘‘The Epistle of . . . and two bearing the name of John, are accepted in the Catholic Church (universally received churches).'' Papias (A.D. 70-163), Tertullian (A.D. 150-220), Clement of Alexandria (A.D. 155-216), Origen (A.D. 184-254), and Irenaeus (c. A.D. 185), disciple of Polycarp, John's disciple, all quoted from this Epistle as "St. John's Epistle." And Eusebius (c. A.D. 324) placed it among universally acknowledged canonical Scriptures.
Dating of this Epistle is difficult because precise information is lacking. Since it appears that this Epistle is a sequel to the Gospel of John, the date would be late A.D. 90-94 or later. Since John's ministry in his later years was at Ephesus, it was likely written from there.
The destination of this Epistle is determined by the title, Catholic - Greek for ‘according to whole,' thus the ‘whole church,' so to the churches at large.
The Purpose of John in this Epistle is fourfold: that the readers: (1) ‘‘know that you have eternal absolute life'' (5:13); (2) ‘‘joy be standing fully filled'' (1:4); (3) ‘‘do not sin'' (2:1); (4) be warned ‘‘concerning the ones continually deceiving you'' (2:26). John also dealt a blow to three branches of Gnosticism in this Epistle: Ebionites (modernists of old) denied the deity of Christ; Docetists denied Christ's true manhood; and Cerinthians denied the union of the two natures of Christ prior to His Baptism.
Characteristics include: exhortative, corrective, loving, and difficult to understand because of extreme contrasts (everything is black or white, no in-betweens).
Three Tests of Life (by Professor Law) -- Tests by which the Christian life may be settled:
1. Righteousness in Life;
2. Love for the Brethren;
3. Orthodoxy of Doctrine.
The Book may be outlined as follows: The Life of Fellowship is:
I. The Joyful Life (1:1-10).
II. The Victorious Life (2:1-17).
III. The Guarded Life (2:18-4:6).
IV. The Life of Assurance (4:7-5:21).