This is part of the sermon Two Ways to Live by Dr. Donald A. Carson, and it really convicted me and hit me between the eyes:
"Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers; but his delight is in the law of the LORD, and on his law he meditates day and night. He is like a tree planted by streams of water which yields its fruit in season, and whose leaf does not whither. In all that he does, he prospers. The wicked are not so, but are like chaff that the wind drives away. Therefore the wicked will not stand in the judgment, nor sinners in the congregation of the righteous; for the LORD knows the way of the righteous, but the way of the wicked will perish."
Psalm 1, verse 1 describes the righteous one in three parts, in terms of what he does not do, "Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers." It describes someone who gets more and more trapped into the ways of sinners. There's a kind of a grinding to a halt: they walk, then stand, then sit. Verse 2 then describes in just one part what the righteous person does, "But his delight is in the law of the LORD, and on his law he meditates day and night."
D.A. Carson told a story from his youth about living in Quebec near a paper plant that stunk up the air and made the water undrinkable. There were a lot of different people that sold bottled water. He remembered one particular company with the slogan, "You are what you drink." They were right in a sense, since the body is over made up of over 90% water.
But the Bible says, you are what you think.
Proverbs says, "As a man thinks in his heart, so is he." When conversion and transformation takes place in a Christian, it must go to the root of your mind. This what Romans 12:1-2 says: "I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect."
You are transformed by the renewing of our mind because you are what you think. As some wag put it, "You're not what you think you are, but what you think...you are." You're not even what you say, because what you say may actually hide what you think. It may be an external civility, a courtesy. It may not even be what you do, because the social constraints may keep you in the straight and narrow in some sense, while inside you're a mass of seething resentments.
That's why Jesus taught us in the Beatitudes that the person who hates has in a sense committed murder already, the person who lusts has in a sense committed adultery already. This is true even if your hand is withheld from either concrete action. The reason, of course, is because you are what you think.
This is why there is so much stress in the Scriptures on thinking God's thoughts after him, and learning to delight in them. Joshua is told in the beginning of his ministry in Joshua 1:8 that, "This Book of the Law shall not depart from your mouth, but you shall meditate on it day and night, so that you may be careful to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success."
Also, think of this passage that is too often overlooked. This is written before there is a king in Israel, but Moses is looking forward to when there will be a king. Deuteronomy 17:18-20 says, "And when he sits on the throne of his kingdom, he shall write for himself in a book a copy of this law, approved by the Levitical priests. And it shall be with him, and he shall read in it all the days of his life, that he may learn to fear the LORD his God by keeping all the words of this law and these statutes, and doing them, that his heart may not be lifted up above his brothers, and that he may not turn aside from the commandment, either to the right hand or to the left, so that he may continue long in his kingdom, he and his children, in Israel."
So the king comes to the throne. What's his first job? Appoint a secretary of state? A commander in chief, perhaps? Construct a cabinet? Audit the books of his predecessor? No. His first obligation is to write out what Moses calls this book of this law. This does not mean downloading it from a cd to his hard drive and letting it pass through his brain. It means writing it out by hand, in Hebrew; so clearly that it becomes his own reading copy for the rest of his life. That's what it means. He is to copy it down and then he is to read it every day.
And the reason he is to read it every day is that so he may learn God's words; and in consequence, not think of himself better than other people, and learn to revere everything God says; and in consequence, not turn from the left or the right. In other words, he is to delight in the law of the Lord, and on His Word meditate day and night. If only those three verses had been followed, all of Israelite history would have been massively different. Just those three verses.
So, the question becomes, "What do you think about when your brain goes into neutral?" When you wake up in the middle of the night, where does your mind go? When you come up to a stop light and you are waiting for it to turn green, you're not thinking about much in particular, where does your mind go? What do you think about? Because, you see, you are what you think.
And unless you put in lots of biblical content, that's not where your mind will go. It's not that to which it will gravitate. You will not think of life shaped by what Scripture says. I don't care how knowledgeable you think you are about Scripture, that's something that you lose, unless you constantly have the input. Unless it's layered in again on top, again and again...and again...and again.
In the next verse, Psalm 1:3, the righteous person is described metaphorically. "He is like a tree planted by streams of water which yields its fruit in season, and whose leaf does not whither. In all that he does, he prospers." The problem in the Middle East is that water is seasonal and in the dry season, everything seems to die. So that tree that is carefully planted near the streams of life has the best chance of living. It is not just planted by one stream, it is carefully planted by the nexus of several streams. That's the significance of the plural here. He is planted (not a wild tree), planted carefully by streams of living water. And its leaf does not whither; that is, there is no dry season, it always shows signs of life. And in due course, it brings forth its fruit in the right season. And whatever it does prospers. This is describing the righteous person metaphorically, not the prosperity gospel.
This is unlike the tree planted next to the wadi, which turns green when there is water around and then looks dead and produces nothing when there is a dry spell. This is not an infrequent contrast in Scripture. Jeremiah puts it even more emphatically with some blistering words when he quotes God in Jeremiah 17:5-8: "Thus says the LORD: 'Cursed is the man who trusts in man and makes flesh his strength, whose heart turns away from the LORD. He is like a shrub in the desert, and shall not see any good come. He shall dwell in the parched places of the wilderness, in an uninhabited salt land. Blessed is the man who trusts in the LORD, whose trust is the LORD. He is like a tree planted by water, that sends out its roots by the stream, and does not fear when heat comes, for its leaves remain green, and is not anxious in the year of drought, for it does not cease to bear fruit.'" (16:26)
Psalm 1:4 says, "The wicked are not so, but are like chaff that the wind drives away." The wicked are not planted by the constant streams of water, and consequently, they dry up and are blown away. They are rootless, dead, profitless. If you look at it from an eternal perspective, it's even more serious yet. Psalm 1:5 says, "Therefore the wicked will not stand in the judgment, nor sinners in the congregation of the righteous; for the LORD knows the way of the righteous, but the way of the wicked will perish."
If we are what we think, then it is essential for us to be planted next to the streams of God's Word and to allow it to transform us and renew our minds. I heard this sermon and came to the stark realization that I was a hypocrite, because my thought life was not what it was supposed to be. I had taken consolation in the fact that I was doing good because I had not physically sinned, but my mind had sinned and it was dwelling more on wicked thoughts than it should. It hit me that if you are what you think, then I needed to think a whole lot differently. How is that possible? Romans 12:2: "Do not be conformed to this world, but be transformed by the renewal of your mind."
You cannot rely on your past knowledge, you must continually renew your mind in God's Word and meditate on it day and night. The time demands of being a teacher and a football coach during football season make it difficult to renew your mind as you ought to; but without doing this, you will be conformed to this world instead of being transformed by His Word. If you are what you think, examine yourself and your thoughts and pray for repentance and a new desire to abide in His Word, to delight in it, and to meditate on it day and night.