A worthy effort is made to distill the gospel message into its simplest and most universal expression. Unfortunately, the simple and the universal, combined, too often yield nothing but ambiguity. This is why we usually do not say, or should be careful of saying, that the gospel message is essentially expressed by the word love, for example. The word is simple, universal, quite accurate—and it will be misunderstood by almost everyone who hears it.
Yet the simple, universal expression of the gospel message is still a worthy effort if it is coupled with the concrete, lived experience of the one who chooses such an expression. For this reason, since the teaching of the apostles, since Christ, since the days of the Law and the Prophets, or even since YHWH rebuked Cain, the paramount expression of the gospel message has been the testimony of personal conduct, which grounds a word like love in the world, in the complex and the particular, so that there may be no ambiguity in what is being preached.