The marvellous display of God’s love described by John has obligations, and he specifies the obvious obligation when he says that each believer ought to love all those for whom God showed his love when he sent his Son to die on the cross. It is inconceivable that a believer could dislike or hate a person for whom his Saviour died.
John will go on in his letter to describe some ways in which believers will show brotherly love. Here, briefly, we can mention some practices that contribute to brotherly love. First, there will be mutual, definite prayer for and with one another. Second, we will speak to one another about the things of the kingdom of God, about the beauty of Christ, about the wonder of forgiveness, and about the prospect of heaven. Third, we will warn and encourage one another as we make our way through a sinful, dangerous world in which our spiritual enemies are attacking us. Fourth, there will be practical expressions of brotherly concern. This is how Christian love develops.
Love is not a hobby. When I was younger, Saturday was the day I spent on my hobbies. On some occasions I would have to do something else and I was not able to participate in my hobbies. Of course, as far as life was concerned, that failure did not matter very much. I sometimes think Christians treat the spiritual life like a hobby – they will give time to it if they can spare it. Yet the spiritual life should be the priority of every Christian because the fact of the matter is this – we are either growing in grace or we are going back. Another word for the spiritual life is love, and the four practices I mentioned earlier can be done at any time and in any place. But they should not be a hobby.
What is the outcome of such living? John tells us that we shall know the presence of the invisible God. Pagans at that time could see their gods in temples, but they could not take the presence of these gods with them because such idols did not have a real existence. No matter how ardent the pagans were, their worship was futile. How different with believers! Living together in love means that we also live together with God. They, in a sense, become the place where God feels at home. What an amazing privilege! What amazing pleasure can be ours when we live in love!