“He shall be like a tree planted by the rivers of water, that brings forth its fruit in its season, whose leaf also shall not wither; and whatever he does shall prosper. The ungodly are not so, but are like the chaff which the wind drives away.” (Psalm 1:3-4)
Trees are often symbols of blessing in the O.T., because they are very common flora in this part of the world. Trees are also stable and strong.
Thus, when the psalmist says that the man of God is “like a tree”, the psalmist is saying that man of God is productive and fruitful. Men of God (and I am not using that word in a gender-specific way, but to refer to all humanity) are fruitful.
Charles Spurgeon rightfully concluded, “The Lord’s trees are all evergreens. No winter’s cold can destroy their verdure; and yet, unlike evergreens in our country, they are all fruit bearers.” Men of God produce fruit because they put themselves in places to grow. They find water; they look for sustenance to encourage their growth. They make sacrifices of time, energy and money to grow.
The opposite is true of an ungodly man. There is no prospering, because there is no effort to grow. There is a distancing from the people of God. There is an unfamiliarity with God’s Word. There is an irregularity of spending time with God in prayer.
A good illustration of this is in Ezekiel 15. Here an outcast vine is symbolized by the nation of Israel – “Then the word of the LORD came to me, saying: ‘Son of man, how is the wood of the vine better than any other wood, the vine branch which is among the trees of the forest? Is wood taken from it to make any object? Or can men make a peg from it to hang any vessel on? Instead, it is thrown into the fire for fuel; the fire devours both ends of it, and its middle is burned. Is it useful for any work? Indeed, when it was whole, no object could be made from it. How much less will it be useful for any work when the fire has devoured it, and it is burned? Therefore thus says the Lord GOD: like the wood of the vine among the trees of the forest, which I have given to the fire for fuel, so I will give up the inhabitants of Jerusalem; and I will set My face against them. They will go out from one fire, but another fire shall devour them. Then you shall know that I am the LORD, when I set My face against them. Thus I will make the land desolate, because they have persisted in unfaithfulness,’ says the Lord GOD.”
That was Israel and that is the ungodly man described in Psalm 1:4.
You are known by your fruits (Matthew 7:16). What evidence is there in your life of you claim to be?
 Spurgeon, pg. 7