Charles H. Spurgeon on Psalms 1:3

"His leaf also shall not wither." He describes the fruit before he does the leaf. The Holy Spirit himself always teaches every faithful preacher in the church to know that the kingdom of God does not stand in word but in power. 1 Corinthians 4:20. Again, "Jesus began both to do and to teach." Acts 1:1. And again, "Which was a prophet mighty in deed and word." Luke 24:19. And thus, let him who professes the word of doctrine, first put forth the fruits of life, if he would not have his fruit to wither, for Christ cursed the fig tree which bore no fruit. And, as Gregory saith, that man whose life is despised is condemned by his doctrine, for he preaches to others, and is himself reprobated. Martin Luther.