The writings of the Apostle John have always had a peculiar charm for the people of the Lord, and I suppose, if for no other reason, for this, that they are particularly addressed to the family of God as such.
If you want truth concerning the kingdom of God in its present aspect, during the mystery days of the kingdom, you will find it in the epistles of Peter, James, and Jude. If you desire truth concerning the Church of God, the Body of Christ, which is being formed by the Spirit during the present dispensation of grace, you find that in the writings of the Apostle Paul. But if you seek truth for the family of God—the believer looked upon as one born again into the divine family—you find that particularly in the writings of the Apostle John. I do not mean, however, that any of these sections of Scripture are confined to the subjects indicated, for while Peter treats primarily of the kingdom, he also speaks of the Church and of the family of God; while Paul treats primarily of the Church, he also speaks of the kingdom and of the family, and while John treats primarily of the family, he also has something to say about the Church and about the kingdom. But God gave a special ministry to each of these New Testament writers, as indicated.