To this point much of John’s letter has been given over to developing the three tests by which a person who has become a child of God may know that he truly is a child of God. They are: the moral test, which is righteousness; the social test, which is love; and the doctrinal test, which is the test of truth or of belief in the Lord Jesus Christ as God incarnate. The tests have been developed one by one, but it has been obvious even as John talks about them that they belong together and that each is important.
But which is most important? In one sense this quite obviously is an illegitimate question, for any approach to the tests is illegitimate if it allows us to minimize one of them. For example, if by saying “Doctrine is most important” we thereby imply that we do not need to live a righteous life or love one another, we are clearly on the wrong track. Or again, if we say, “Love is so important that we do not need either obedience or doctrine,” that too is wrong and dangerous. On the other hand, there are senses in which a question about the most important test is valid. We can ask it in terms of our need, for instance: Which do we most lack? Or we can ask it in terms of John’s interests: upon which does John lay most emphasis as he writes this letter? Interestingly enough, the answer to both these forms of the question is: the test of love. For we need to love, and it is upon love that John himself seems to lay the greatest emphasis.
This does not mean that John neglects doctrine. The apostle who composed the fourth Gospel in order that those who read it might “believe that Jesus is the Christ, the Son of God” is not going to minimize the truths concerning Jesus Christ, nor any other doctrines. Nor does it mean that he neglects the need to live a righteous life. John has already said that the person who claims to know God and who does not live a righteous life is a liar. However, it does mean that John saw a lack in this area and therefore also saw that the need to show love demanded great emphasis. We remember that John was writing to those who had resisted the Gnostic errors and excesses. They had not abandoned the truth, nor had they fallen into loose living. But did they love? Did they really love one another?
In seeing why John presses the point as he does, particularly in this section of the letter, we also see why the point must be pressed today precisely among the most orthodox and moral sectors of the Christian Church. We recognize that it is possible for a group of Christians to be very orthodox in theology and moral in outward behavior and yet have very little love for one another.
Nowhere does John stress the need to love more than in these verses from the fourth chapter. It is not the first time that he has considered the test of love, of course. The test occurred first in 2:7-11, in which it is related to the “true light.” The test occurred a second time in 3:11-18, in which it was related to “eternal life.” Each of these has been important, but in a sense both have been a preparation for this third development of the test in which it is related, neither to light nor life, but to the very nature of God, which is love. This statement (that “God is love,” 4:8, 16) is probably the high-water mark of the epistle and these verses its “sublimest height.”1
1Robert Law, The Tests of Life (Grand Rapids, MI: Baker, 1968), 246.