When Jesus says this, He is speaking of two different categories of persons - those whose fundamental orientation of the heart is toward God and those whose fundamental orientation of the heart is not. Can good fruit come from a thornbush? Of course not.
We, however, have appropriated this teaching to mean much, much less. For us, when we talk about fruit, we are talking about something much more vague - "right" and "wrong." Those who produce good fruit are those who are doing "right;" those who produce bad fruit are those who are doing "wrong."
And we shall know them by their fruit.
Here is the problem with that: not every apple on the tree is edible. But that doesn't make it a thornbush.
See, we are tempted to look at sinners and shake our heads. He's just not producing good fruit, we say. He's just not what he appears to be, we conclude. He's not really a "Christian." Just look at all those rotten apples.
We do this more with certain sins than with others. For example, we might be willing to look at a woman who has told a lie and determine that she might still be a good woman; she just has one rotten apple on her tree. Or we might look at a man who views pornography or cheats on his wife and say this, too, might just be one rotten apple. We are able to say this because we look at the overall testimony of these persons' lives, and we see all of the good, godly things they are doing. Maybe we see them honestly wrestling with their sin, trying to find the way out of the darkness and back into the light. And we are not ready to condemn them based on one apple that grew in their life that just isn't edible.
But we are less willing to reach the same conclusion with, say, someone engaged in homosexual activity or who lives with a same-sex attraction. Someone told me last week that he doesn't know any godly homosexuals. "How could I?" he asked, and quoted the above teaching of Jesus. You will know them by their fruit.
And I said to him what I said here: not every apple on the tree is edible. But that doesn't make it a thornbush.
The truth is that if you judge a tree by its worst fruit, they're all worthless. Burn 'em down. There is nothing worth saving in the whole orchard. Nothing. But if you look beyond that one apple you can't eat, if you're willing to keep searching the tree for fruit, you'll find it, if it's there.
You'll find so-called sinners who still have the life of Jesus flowing through them. You'll find liars proclaiming God's truth. You'll find adulterers being faithful to their churches. You'll find murderers seeking after eternal life. You'll find scammers holding out one real deal. You'll find homosexuals as the bride of Christ. You'll find them, if you can pull your eyes away from a few rotten apples and consider what you've got here.
It's still a good tree.
See, when Jesus talks about this concept, He talks about trees that produce fruit and trees that don't: thornbushes and real trees. He doesn't talk about "good" fruit and "bad" fruit in the same way that we do - thornbushes don't even produce bad apples. Only good trees can do that. Only a tree that's got the right root system, the right life flowing through it can produce fruit at all; it just so happens that not all that fruit is edible.
"Bad" fruit isn't fruit from the good tree that rots before it is picked or that never matures fully or that, for whatever reason, cannot be eaten. "Bad" fruit is no fruit at all. Or in some cases, it's mock fruit - poison berries on a thornbush. (But this gets a little more complicated, so I will deal with this a bit tomorrow.)
Today, the question is this: are you judging a tree by its fruit, or by its worst fruit? Are you willing to burn down the orchard because not every fruit is edible? Is it possible that a good tree, a really good tree, make a bad apple every now and then?
Is it possible even if you don't necessarily like apples?