This section does little more than bring together themes that have been introduced throughout the previous passages. They have been used there more or less as illustrations of the motifs of light and righteousness, aspects of God's nature defining the basis of fellowship. But here they are derived directly from the proclamation that God is love. For that reason we have a third major movement in the symphony of this great letter.
It is important to recognize that the declaration God is love must be heard in tandem with the other two motifs of this letter. Many have failed to do this and the result is a sentimentality that loses touch with the holiness of God (reflected in the idioms of “light” and “righteousness”). Neither is love alone to be considered the test of life. “John makes it plain enough elsewhere that the true child of God both believes and loves ([3Jn] 3:23)” (Marshall, 211).
John addresses three major truths in this section, and they are interwoven throughout, which is a characteristic of his literary style.
A. God as the Source of Love
The implication of this point is theologically crucial: Our love is a response to God's love and not the basis of his love for us. A further truth is that our love is enabled by God's love and not independently produced. God's gift of his Son for our salvation is that which defines the meaning of love, as John has stated before. This thought is the occasion for a further emphasis on the relation of love and sound doctrine. If God's gift of his Son was a charade (as the false teachings would imply) and the Son was not a real human being fully involved in our history, God's love is called into question. Hence, belief that the human Jesus was the Son of God is essential to the validity of the claim that God is love. There is no artificial connection between love and sound doctrine and no tension between them (Bruce, 110-11).
B. Living the Life of Love
Interestingly, John does not draw the conclusion that because God loved us, we ought to love him; rather he declares that we ought to love one another (v. 11). This in no way suggests that love for God is an illegitimate concept. The first commandment enjoins it. It does imply that a mysticism that could result from an exclusive preoccupation with love for God is misguided. Love for God must show itself in love for a tangible human being. This shift not only recognizes the finite difficulty of loving a reality not seen, but the importance of showing love toward those who need love. In a word, love for God will show itself in self-sacrificing love for others. They are inseparable truths.
C. Love Can Be Perfect
Here in 4:17-18 is another central Wesleyan text, providing reinforcement to the claim for the present possibility of perfect love. Such love produces boldness, a distinctive emphasis of this letter (see 2:28; 3:21; 22; 5:14, 15). Here it is future oriented and refers to the Day of Judgment. Absence of fear (boldness) derives not from a sense of self-sufficiency but from the relation of child to Father. Love and fear of punishment are incompatible. This does not imply flawless behavior on the part of the child; any claim to perfection at this level can result only in bigotry. Rather it is God's full and free acceptance and the believer's trust in his love that elicits a full confidence that excludes fear and uncertainty.