The First of these Epistles is not addressed to any persons in particular; but was written to warn all Christians not to listen to the false teachers, who were then leading many into serious error. Some of these false teachers, pretended that Jesus was not really man; and that, as He had no real body like ours, He did not really suffer crucifixion. Others, on the contrary, taught that He was only man. Both doctrines were equally fatal to the hopes of Christians: if Jesus Christ did not share our human nature, He could not atone for the sin of man; if He were only man, however free from sin Himself, He could not atone for the sins of His fellow mortals. Thus a firm belief in Jesus Christ as God and Man, is absolutely necessary for all who look for salvation through Him. Another set of false teachers taught, that those who believed themselves to be justified by faith, and so freed from the restraints of the Levitical Law, might sin without fear of punishment. St. John cautions all Christians not to be led away by these, or any other false doctrines; and he shows them how very different they are from the truths contained in the Gospel as taught by Jesus Christ, and fully explained by His Apostles. St. John, in this Epistle, speaks much of the love of God towards His creatures, and of the duty of all men to love Him and their fellow creatures for His sake.
The Second Epistle of St. John was probably written from Ephesus, his usual abode at this time. This Epistle is addressed to some particular lady, to warn her and her children not to listen to the dangerous doctrines of false teachers.
The Third of St. John's Epistles is written to a man named Gaius, who is supposed to have been converted by the Apostle, who therefore speaks of him as one of his children: a very usual figure of speech with teachers, respecting those whom they converted. In this way St. Paul calls Timothy his "son." In the Acts of the Apostles, and in the Epistles, we meet with the name of Gaius five times; and four different persons seem to be meant. Gaius, of Macedonia (Acts xix.); Gaius, of Derbe (Acts xx.); Gaius, whom St. Paul baptized at Corinth (1 Cor. i.), and who lodged that Apostle in his own house at Corinth (Rom. xvi.); and this Gaius, to whom St. John writes his Epistle; whether he was one of those already mentioned, we cannot know.
The object of this Epistle from St. John, seems to have been to praise Gaius for his steady faith, and for having shown kindness to some Christian strangers, who had passed through the place where he lived: at the same time, St. John cautions him to have nothing to do with a teacher named Diotrephes, who had denied St. John's authority, and set himself up as the head of a party, in opposition to the Apostles.
St. John entreats Gaius to do, what may equally apply to each one of us, for he says, "Follow not that which is evil, but that which is good." He also recommends to him Demetrius, of whom we know nothing, except that he was a good man. This letter to Gaius is very short, because, as St. John writes, he hoped shortly to meet and talk to him.
St. John spent the last years of his long life at Ephesus, and there, about a.d. 99, he wrote that very valuable and beautiful portion of Holy Scripture known to us as "The Gospel according to St. John." When St. John wrote, he was of course well acquainted with the Gospels of St. Matthew, St. Mark, and St. Luke, and also with the Book of Acts, for they had all been written many years before this time. He does not, therefore, repeat much of what they tell us, but gives an account of many things which they do not mention; and repeats especially much of what his blessed Lord said at different times to His disciples. There was a good reason for this.
Even by this time, many errors had crept into the Christian Church, as has already been said, when speaking of St. John's First Epistle.
St. John, therefore, wrote his Gospel to correct these errors, and to show all men, that Jesus Christ was truly and indeed the Son of Man and the Son of God: the Word that was from the beginning with God, and was God, and was made man, that He might suffer for us.
The Gospel of St. John completed the Canon of Scripture; that is, those writings which are undoubtedly written by inspiration of God, and are, therefore, to be the general rule of Christian faith and practice.