For there is no good tree which produces corrupt fruit, nor a corrupt tree which produces good fruit;
The Lord has been teaching His disciples how to treat other people. Now He turns from what they do to what they are, and asks what kind of tree is standing there.
The picture is not about a tree trying harder. It is about what a tree is. One commentator points out that the Lord settles the matter at the level of nature, and that no one can change a nature:
Then He shows how clearly it is a question of nature. "For no good tree bears bad fruit, nor again does a bad tree bear good fruit." You cannot change the nature. The Lord did not yet show how the two natures act, or how allowing the old can hinder the fruits of the new creation. He simply points out that there are two natures. He does not speak here of the two natures existing side by side in the same person, though that is in fact true even of a real believer.
The verse follows straight on from the Lord's words about the log in your own eye. Judging yourself is the way to clear sight, and it reaches deeper than the crop:
Judging yourself, and not your brother, was the way to gain clear moral sight. If the tree is good, the fruit will be good. Self-judgment applies to the trees. This is always true. In self-judgment, you do not only correct the fruit; you correct yourself. And the tree is known by its fruit — not only by good fruit, but by its own. The Christian bears the fruit of the nature of Christ.
The picture answers a practical question: what is fruit for? Notice that it cannot be tied on from outside:
Anyone can tell that the tree lives and is healthy, because of the crop it is bearing. Its life shows itself in fruit. If there were no fruit the tree had better be cut down as a waste of the ground. But there is fruit. It is the necessary evidence of the life. The fruit does not produce the life, but the life the fruit. You might decorate the tree with fruit, but that would not give it life.
The Lord is speaking to a crowd of disciples, and not all of them were real. From this verse on, the subject is the claim to be a follower — and how to test it:
From verse 43 the outward profession of discipleship is in view. The Lord may have had someone like Judas especially in mind in speaking this way. Among those who took the place of being His disciples there might be "an evil man" as well as "a good man." Their fruits tell them apart, seen in both speech and action. Fruit reveals nature. We cannot see into the secrets of nature, either in a tree or in a man. But we can easily and correctly work out the nature from the fruit.
If no one can improve a nature, the verse leaves only one door open. God must put something into the heart that was not there before:
In these verses the Lord strikes at people who pretend to be good while His grace has never touched their hearts. They have no new life, so they are still under sin. A good person is one whose heart is purified by faith in the Son of God, for by nature "no one does good, not even one" (Rom. 3:12). Only the grace of God can make a difference in the person. In this case God plants a "good treasure" in his heart — the knowledge of the glory of God in the face of Jesus Christ, given to "jars of clay" (2 Cor. 4:6-7). Only good can come from this, however weak the vessel may be.
- Root. The verse works backwards from fruit to nature. What a person produces is decided by what a person is, and a nature cannot be talked out of acting like itself.
- Self. The self-judgment the Lord calls for reaches past the fruit to the tree. Real self-judgment corrects not just what you do, but who you are.
- Evidence. Fruit proves life; it never creates it. Decorating a dead tree with fruit changes nothing about the tree.
- Test. Because nature shows itself in speech and action, a claim to be a disciple can be checked. We cannot see inside a man, but we can read the crop.
- Remedy. No one grows good by trying harder. A heart purified by faith in the Son of God receives a good treasure. Only good comes from that source, however weak the person who carries it.
for every tree is known by its own fruit, for figs are not gathered from thorns, nor grapes vintaged from a bramble.
The Lord ends His teaching with a test anyone can run: nobody picks figs off a thorn bush. So what does fruit prove, and whose tree does He check first?
The fruit saying sits inside a larger argument about what a person is by nature.
Then He shows how clearly it is a question of nature. "For there is no good tree which produces corrupt fruit, nor a corrupt tree which produces good fruit." You cannot change the nature... At this point the Lord did not yet show how the two natures act, or how allowing the old one can hold back the fruits of the new creation. He only points out that there are two natures. He does not show them living side by side in the same person, which is what really happens even in a true believer.
Matthew and Luke word the same lesson differently. Matthew turns the eye outward on other people; Luke states a rule that covers every tree.
"Every tree is known by its own fruit." This is peculiar to Luke — I mean the putting it in so strong a manner. Matthew says, "By their fruits you shall know them." Luke makes it more comprehensive and emphatic.
The two words its own carry weight. Fruit can look fine and still not come from Christ.
"Every tree is known by its own fruit." Not only bearing fruit, but fruit that Christ produces should be ours. An upright nature produces fruit too, like that of the young man who came to Jesus. But that was not divine fruit; it was the tree's own fruit. Where Christ is the root and the stock, the fruit is Christian fruit — fruit that will remain (John 15:16). Two men may go along together up to a point. Then some test for Christ comes: one goes on with Him, the other turns aside. "Its own fruit" — fruit shows itself, springs of itself.
Just before this, the Lord spoke about the speck in a brother's eye and the log in one's own. So the disciple runs the fruit test on himself first.
Judging yourself, and not your brother, was the way to clear moral sight. If the tree is good, the fruit will be good. Self-judgment applies to the trees. This is always true. In self-judgment, it is not only the fruit that is corrected; it is oneself. And the tree is known by its fruit — not only by good fruit, but by its own. The Christian bears the fruit of the nature of Christ.
If the crop follows the root, work on the branches is wasted. One writer turns the picture into a warning about cultivating the flesh.
So if man seeks to cultivate the flesh, even in its fairest forms, he is doomed to disappointment. If I cultivate a thorn-bush under the illusion that it is a vine, I shall only increase the size and number of the thorns and not succeed in getting one grape. No one would be so foolish as to mistake a thorn-bush for a vine. But sadly, in moral and spiritual things, even leaders in the Christian world are making a worse mistake, and the consequences are graver.
Another writer asks what God makes of the actions of people who have not been born again.
The outward character of people's actions does not matter. Some actions win the applause of others; some bring down their condemnation. But as long as they come from people who have not been born again, they are nothing but evil in the sight of God... So, as Luther said, it is not a question of doing, but of being; not a question of the character of actions, but a question of nature.
Thorns are not a neutral picture in the Bible. They have a history.
Thorns and thistles came into the world as a result of Adam's sin. God drove him out of the beautiful garden of Eden, and the ground would be cursed because of him and would produce thorns and thistles. Many times in the Bible thorns picture wicked people, and just as thorns are burned in the fire, the prophets spoke of a righteous God punishing the wicked.
What you keep in your heart comes out in what you say and do.
If we foster wrong and unkind thoughts sooner or later they will become wrong and unkind words and deeds. If, on the other hand, we treasure the words and teaching of our blessed Lord, we shall speak kind words and act in kindness and love as He did.
- Root — the nature of the tree decides the crop. There are two natures, and you cannot change a nature.
- Own — Luke's "its own fruit" goes further than Matthew's "by their fruits." Fruit springs of itself, and Christian fruit is the fruit Christ produces.
- Self — the test aims at the examiner first. Self-judgment corrects the tree, not just the fruit.
- Futility — cultivating a thorn bush only grows more thorns; the question is being, not doing.
- Evidence — what fills the heart comes out in words and deeds. Treasure Christ's teaching, and kindness follows.
The good man, out of the good treasure of his heart, brings forth good; and the wicked [man] out of the wicked, brings forth what is wicked for out of the abundance of the heart his mouth speaks.
The verse closes the Lord's picture of the tree and its fruit with a rule about speech. It raises the sharpest question of the passage: not how a person talks, but what kind of person is talking.
The Lord is not measuring behaviour here. He is exposing what a person is. One writer notes how Luke sharpens the wording:
Then He shows plainly that it is a question of nature. "For no good tree bears bad fruit, nor again does a bad tree bear good fruit." You cannot change the nature. … "Each tree is known by its own fruit." This is unique to Luke — I mean the way Luke states it so strongly. Matthew says, "You will recognize them by their fruits." Luke makes it wider and stronger.
Nature stays hidden, so fruit is how we read it. Here that test falls on people who claim to follow Jesus:
From verse 43 the Lord looks at the outward profession of discipleship. He may have had someone like Judas in view as He spoke. Among those who took the place of being His disciples there might be "an evil man" as well as "a good man." Their fruits show which they are, in both speech and action. Fruit reveals nature. We cannot see into the hidden nature of a tree or a man, but the fruit tells us what it is, easily and correctly.
So where does a good store in the heart come from? One commentator traces it to grace, not to anything people own by nature:
In these verses the Lord strikes at people's pretence of goodness while their hearts stay untouched by His grace. They are not born again, so they are still under sin. A good person is one whose heart is purified by faith in the Son of God, for by nature "no one does good, not even one" (Rom. 3:12). Only the grace of God can make a difference in the person. In this case God plants a "good treasure" in his heart. It is the treasure of the knowledge of the glory of God in the face of Jesus Christ, given to "jars of clay" (2 Cor. 4:6-7). Only good can come from this, however weak the vessel may be. Without this good treasure a person has only "an evil treasure" in his heart, and his mouth soon expresses it, for whatever fills the heart most is what the mouth will speak.
The saying also turns back on the listener. Luke's version, one writer observes, is a rule for self-examination:
But Luke presents the matter far more as a moral principle. It is true of every man that out of the abundance of the heart his mouth speaks. This is an important test for the state of our souls. Our lips betray the condition of our heart — of our affections.
A front held in public cannot last:
What is really filling my heart will come off my tongue. And therefore you can always tell what my heart is occupied with, because I have a tongue. I cannot long deceive you.
It is rarely a speech that exposes us. One writer points to a single word:
The evil is not the things themselves dug out of the earth, but the love in the heart for them. "Out of the abundance of the heart the mouth speaks." An impatient word betrays the heart. A blow I may restrain and yet utter the word.
So the cure works at the source, not at the lips:
"And these words that I command you today shall be on your heart" — at the very source of all the issues of life. This is very precious. Whatever is in the heart comes out through the lips, and in the life. How important then, to have the heart full of the word of God! It should be so full that we have no room for the vanities and follies of this present evil world… So we can judge what is in the heart by what comes out of the mouth. The tongue is the organ of the heart — the organ of the man… the heart is the mainspring of our entire moral condition.
- Nature — The tree decides the fruit. Luke states it in the strongest form: each tree is known by its own fruit. The question is what a person is, not what they do.
- Treasure — By nature no one is good. Grace plants the good store in the heart. Without it, only an evil treasure is there to draw on.
- Mouth — Whatever fills the heart most reaches the tongue. Words are where the hidden store becomes public.
- Test — Luke makes this a test for our own souls. Our lips betray our affections, and one impatient word is enough.
- Source — The heart is the mainspring. So fill it with God's word, until there is no room for the follies of this world.