Because God's children have experienced such love, the command that comes to them to love each other is not the "ought" of external compulsion but the "ought" of internal constraint (Bruce 1970:109). On its own, the commandment cannot provide the incentive or the power to fulfill it, and this might foster either discouragement or indifference. But those who are in touch with the very source of love, who have been shown what love is and who are the recipients of a great and healing love, can receive the command ment with hope and joy. For they are not commanded to do something that is alien to their experience or beyond their ability to learn and to do.
So strong is John's confidence that the Christian community will fulfill this command that he writes that mutual Christian love manifests the presence and action of the invisible God (v. 12; Smalley 1984:246). When he writes no one has ever seen God, he calls to mind the same statement in the Gospel of John (1:18). In both cases, he is not trying to tell us what God is like but how God is known. And God is known not only in the revelation that comes to us in Jesus (Jn 1:18) but also by the manifestation of our love for each other (1 Jn 4:12). The love of believers makes evident and concrete the activity of God among them. In fact, when the Elder writes that this is how [God's] love is made complete, he means that it reaches its intended goal when it flows from God, through us, to our fellow believers. The love with which God loved us must in turn be extended to the fellowship of believers.
In short, God not only gives us the command to love but has also modeled for us what true love is, just as Jesus modeled love for his disciples when he washed their feet before his death (Jn 13:1-17). Love that does not express itself concretely and in service to others is not love (1 Jn 3:16-18). But even more, God also empowers us to love. By con fession of the Son whom God has sent, we are born of God and come to know God, who is love (v. 7); we are given life (v. 9); our sins are forgiven (v. 10). We come into the realm of life and love, in which we are given life and are empowered to extend the same kind of life-giving love to others. We come to know the source of love.
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