In the figure of ver. 3 there are revealed three aspects of godly character.
I. Its variety. The comparison is with a fruit-tree, not of any particular kind, but one of that large class of trees. The variety which God stamps upon nature He means to have reproduced in character.
II. Its Divine culture. The godly man is not like a tree that grows wild. He is like a tree planted, and that in a place which will best promote its growth. Godly character is developed under God's special supervision and with God's own appliances.
III. Its fruitfulness. God's tree by God's river must be a fruitful tree. Notice: (1) The words are " hisfruit," not any other tree's fruit. (2) "In his season." The seasons are different for different fruits. The latest fruit is usually the best. But, early or late, the fruit of godly character is seasonable.
M. R. Vincent, Gates into the Psalm Country,p. 3.