The great theme of the Gospel and the Epistles of John is life. There is, however, this difference; in the Gospel we see the perfect manifestation of eternal life in Christ, while the Epistles present the fruits and the proofs of this life in believers.
In the course of the Epistles, the apostle warns us against antichrist and false prophets, and speaks of the time in which he wrote as being characteristically the "last hour". We may thus conclude that the Epistles were probably the latest writings of the New Testament, and that, when the apostle wrote, the ruin of the Church in responsibility had already commenced.
This gives to the Epistles a deep importance for believers in these last days, inasmuch as we learn thereby that, in a day of ruin, though the Church may be shorn of the outward power and display that marked it in Pentecostal days, it is still possible for the individual believer to get back to that which is vital—the life that was set forth in perfection in Christ from the beginning. No ruin of the Church, no corruption of Christendom, can touch that which is true in Christ. Thus, the life that was set forth in Him, and communicated to the believer, can still be lived and bring forth its blessed fruits in the power of the Spirit.
One has well said that, "God, in giving me eternal life, has also given me a nature and capacity to enjoy Him forever." We may add that these Epistles make it abundantly clear that, in spite of all the ruin of the Christian profession and the scattering of the people of God, we can, in the power of this new life, enter into our eternal portion and enjoy fellowship with divine Persons and with one another even now.