Let’s first view the whole of verse 1: “Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world.”
I think we normally take this word of exhortation to apply to spiritual influences on the outside of us (external). But what do you think about applying this warning to spiritual activity inside of us (internal)? I believe that this really is the most important arena for testing spirits. Insofar as you and I are concerned personally, it is the very worst place in the world to allow deception. Deception out there somewhere is not near as serious for me personally as deception within me—self deception. If the spirit within me does not measure up in the right way, I run the risk of being one of those “false prophets” that John warns of—and carry on so self-deceived so as to not know it.
So let’s ask this point-blank question of ourselves: What kind of spirit makes me tick?—guides and controls me? Is it one that is truly from God? Or is it from elsewhere—not from God? To help us test appropriately, we are given in this reading two basic standards for evaluation. I’ll list them in the form of two questions:
Please understand that it is only as we pass this important test that we can claim the important promise that “the one who is in you (me) is greater than the one (spirit of deception) that is in the world” (v. 4).