The psalmist is indebted both to Jeremiah (17:5–8) and to Ezekiel (47:12) for his comparison of a good man to a growing tree. Turning to the other side of the picture, the psalmist now describes the morally loose, the evildoers. How vivid the contrast which he paints! For the wicked compare with the good as wind-driven chaff compares with a securely rooted tree. We note here a characteristic Hebrew idea that in goodness there is permanence: it has hold upon reality. In evil there is nothing substantial.