Judging Fruit

Matthew 7:15-20 (ESV)
"Beware of false prophets, who come to you in sheep's clothing but inwardly are ravenous wolves. [16] You will recognize them by their fruits. Are grapes gathered from thornbushes, or figs from thistles? [17] So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. [18] A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. [19] Every tree that does not bear good fruit is cut down and thrown into the fire. [20] Thus you will recognize them by their fruits.
I think the problem most have with interpreting this verse is they let the world rather than God decide what is good fruit and what is bad fruit. Good Fruit is so often thought of as outward reform of someone’s moral life, and it ends there. But then people have been known to clean themselves up for all sorts of reasons. Yet if one bothers to try it is normally quite easy to smell the smell of rotten fruit under the cologne and perfume. Or perhaps it is thought of in terms of material wealth despite everything Jesus says concerning that sort of thing.
Now of course, neither moral reform nor material wealth are bad in and of themselves. But that is just it. They are not good indicators of anything. Especially when the world is the one deciding what is morally good or evil.
False prophets come, they turn one away from faith in Christ. Without Christ it is impossible to bear good fruit. The fruit they produce is anxiousness concerning ones own salvation. This is the worst fruit of them all. False belief, despair and other great shame and vice the one leads to the other and the other.
But the good fruit of faith that is produced by Jesus Christ is certainty in knowing that your sins are forgiven. It is a calm security that does not manifest itself in self-righteousness or despair. But a calm love for your neighbor, not born of a selfish desire for salvation of your own soul, but concern for his or hers. We know in whom we have salvation, He has overcome the world, our only hope is that when the time is right our neighbor will hear and know this also.