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.
Like a tree-see Jeremiah 17:8. The image is of a desert date palm that has been firmly planted in a well-watered oasis. (Nelson Study Bible) The image of tree also calls to mind the personfication of Wisdom in Proverbs. "It is a tree of life to them that hold fast to it and all of its supporters are happy." (Prov. 3:18) This verse is chanted after the reading from the Torah scroll. Torah itself is called etz chayim (a tree of life). Thus we have a connection between studying Torah (a tree of life) and being like an ever fruitful tree.
Shall prosper-from this we may get the mistaken notion that if you study Torah you will never lack for anything. The idea that if you just meditate on God's Word you won't have to worry about your future finances is not what this verse is saying. NSB notes: The righteous person is always useful and productive to the Lord.