For all who take their delight in living by God’s Word, there is prosperity. Under the image of a fruitful tree, the psalmist declared that whatever the righteous do will prosper (cf. 92:12-14). Two qualifications need to be noted. First, the fruit, that is, the prosperity, is produced in its season and not necessarily immediately after planting. Second, what the godly person does will be controlled by the Law of God (1:2). So if a person meditates on God’s Word, his actions will be godly, and his God-controlled activities will prosper, that is, come to their divinely directed fulfillment.
Ross, Allen P. “Psalms.” The Bible Knowledge Commentary: An Exposition of the Scriptures. Ed. J. F. Walvoord and R. B. Zuck. Vol. 1. Wheaton, IL: Victor Books, 1985. 790. Print.