When a birth takes place the individual involved is not born into isolation, nor is he a totally unique individual in the sense that his characteristics and attributes have no connection with those who have gone before. For one thing, he is born into a family and into family relations. For another, he possesses at least some of the characteristics of the one who has engendered him. Spiritually, this means that the child of God exhibits those characteristics about which the letter has been teaching.
The first characteristic is love, both for the parent and for the other children. Earlier John has said that it is a characteristic of the child of God to love, since God is love (4:7). Now he shows equally that it is a characteristic of the child of God to be loved by those who are also members of God’s family. Verse 2 is not altogether unambiguous, however; it can have two meanings. If the opening words, “by this,” refer to what follows, as is generally the case in John’s writings, the meaning would be that if we are uncertain whether or not we love other Christians, we may reassure ourselves by determining whether or not we love God the Father. In other words, love of God becomes the fixed point from which we may determine our attitude to others. It may be said in support of this view that John undoubtedly held that love of God and love of man belong together, so that one may begin at either pole and arrive at the other. But the problem is that this form of reasoning is the opposite of what has been affirmed throughout the letter. It is by our love for one another that we are assured of our love for God; this is John’s reasoning. Besides, just a few verses earlier John has argued that we cannot love God unless we love others.
The words of verse 2 are capable of another meaning, however. In this reading the words “by this” refer to what comes before. So the passage may be translated, “By this [namely, the truth that if one loves the parent he inevitably loves the child] we know that, when we love God, we love the children of God and keep God’s commandments.”
The logic would be: 1) Everyone who loves the parent loves the child; 2) Every Christian is a child of God; 3) Therefore, when we love God we love our fellow Christians. Love for others is therefore a direct result as well as an obligation of having become one of God’s children.
Love divorced from obedience to the commands of God is not love, however. So John immediately passes from love to the matter of God’s commandments, saying, “For this is the love of God, that we keep his commandments.” Christians frequently attempt to turn love for God into a mushy emotional experience, but John does not allow this in his epistle. Love for the brethren means love that expresses itself “in deed and in truth” (3:18). Similarly, love for God means a love which expresses itself in obedience to all His commandments.
At this point John says a striking and quite unexpected thing. He says that “his commandments are not burdensome.” This does not mean that total obedience to all the commands of God is an easy thing to achieve; for if that were so, Christians would not sin, and John says elsewhere that they do.
John probably means two separate things by this statement. First, he may be thinking of the contrast which Jesus made between the commands of the scribes and Pharisees, which were “heavy burdens and grievous to be borne” (Matt. 23:4; cf. Luke 11:46), and His own commands, which were easy—“For my yoke is easy, and my burden is light” (Matt. 11:30). The Pharisees had created thousands of minute requirements by which the central commands of the law were to be guarded. But they were not God’s commands, nor were they life-giving. They were burdensome. Jesus cut through these man-made rules to expose the central heart-attitudes which were required but which God would Himself supply in His regenerated people.