The Idol Factory - Why 1 John Ends with a Command

David Powlison:
The relevance of massive chunks of Scripture hangs on our understanding of idolatry. But let me focus the question through a particular verse in the New Testament which long troubled me. The last line of 1 John woos, then commands us: “Beloved children, keep yourselves from idols” (1 John 5:21).
In a 105-verse treatise on living in vital fellowship with Jesus, the Son of God, how on earth does that unexpected command merit being the final word?
Is it perhaps a scribal emendation?
Is it an awkward faux pas by a writer who typically weaves dense and orderly tapestries of meaning with simple, repetitive language?
Is it a culture-bound, practical application tacked onto the end of one of the most timeless and heaven-dwelling epistles?
Each of these alternatives misses the integrity and power of John’s final words.
Instead, John’s last line properly leaves us with that most basic question which God continually poses to each human heart.
Has something or someone besides Jesus the Christ taken title to your heart’s trust, preoccupation, loyalty, service, fear and delight?
It is a question bearing on the immediate motivation for one’s behavior, thoughts, and feelings. In the Bible’s conceptualization, the motivation question is the lordship question.
Who or what “rules” my behavior, the Lord or a substitute?
The undesirable answers to this question—answers which inform our understanding of the “idolatry” we are to avoid—are most graphically presented in 1 John 2:15-17, 3:7-10, 4:1-6, and 5:19. It is striking how these verses portray a confluence of the “sociological,” the “psychological,” and the “demonological” perspectives on idolatrous motivation.
The inwardness of motivation is captured by the inordinate and proud “desires of the flesh” (1 John 2:16), our inertial self-centeredness, the wants, hopes, fears, expectations, “needs” that crowd our hearts.
The externality of motivation is captured by “the world” (1 John 2:15-17,4:1-6), all that invites, models, reinforces, and conditions us into such inertia, teaching us lies.

The “demonological” dimension of motivation is the Devil’s behavior-determining lordship (1 John 3:7-10,5:19), standing as a ruler over his kingdom of flesh and world.
In contrast, to “keep yourself from idols” is to live with a whole heart of faith in Jesus. It is to be controlled by all that lies behind the address “Beloved children” (see especially 1 John 3:1-3,4:7-5:12). The alternative to Jesus, the swarm of alternatives, whether approached through the lens of flesh, world, or the Evil One, is idolatry.
Justin Taylorhttp://thegospelcoalition.org/blogs/justintaylor/2011/11/26/why-1-john-ends-with-a-command/