Hereby perceive we the love of God, because he laid down his life for us: and we ought to lay down our lives for the brethren. 1 John 3:16. RC 317.1
After the ascension of Christ, John stands forth as a faithful, earnest laborer for the Master.... He enjoyed the outpouring of the Spirit ... and with fresh zeal and power he continued to speak to the people the words of life, seeking to lead their thoughts to the Unseen. He was a powerful preacher, fervent, and deeply in earnest. In beautiful language and with a musical voice he told of the words and works of Christ, speaking in a way that impressed the hearts of those who heard him. The simplicity of his words, the sublime power of the truths he uttered, and the fervor that characterized his teachings, gave him access to all classes. RC 317.2
The apostle's life was in harmony with his teachings. The love of Christ which glowed in his heart led him to put forth earnest, untiring labor for his fellow men, especially for his brethren in the Christian church. RC 317.3
Christ had bidden the first disciples love one another as He had loved them. Thus they were to bear testimony to the world that Christ was formed within, the hope of glory. “A new commandment I give unto you,” He had said, “That ye love one another; as I have loved you, that ye also love one another” (John 13:34). At the time when these words were spoken, the disciples could not understand them; but after they had witnessed the sufferings of Christ, after His crucifixion and resurrection, and ascension to heaven, and after the Holy Spirit had rested on them at Pentecost, they had a clearer conception of the love of God and of the nature of that love which they must have for one another.... RC 317.4
After the descent of the Holy Spirit, when the disciples went forth to proclaim a living Saviour, their one desire was the salvation of souls. They rejoiced in the sweetness of communion with saints. They were tender, thoughtful, self-denying, willing to make any sacrifice for the truth's sake . In their daily association with one another, they revealed the love that Christ had enjoined upon them. By unselfish words and deeds they strove to kindle this love in other hearts. RC 317.5
Such a love the believers were ever to cherish. They were to go forward in willing obedience to the new commandment. So closely were they to be united with Christ that they would be enabled to fulfill all His requirements. Their lives were to magnify the power of a Saviour who could justify them by His righteousness.—The Acts of the Apostles, 546-548. RC 317.6