Verse 18. — He is light upon the face of the water. 79. The wicked are light before every wind of temptation or of error. — He returns from the plural number to the singular, because for the most part one man begins the evils, and by imitation many follow after. But the fault is principally his who furnished to the perverse who follow the examples of iniquity. Whence the sentence often returns to him who was the author in the fault. But the surface of the water is driven hither and thither by the breeze, and, made firm by no stability, is moved everywhere. The mind of the wicked, therefore, is lighter than the surface of the water, because whatever breeze of temptation touches it, it draws it without any delay to reconsideration.
For if we consider the wavering heart of any perverse man, what else do we behold than the surface of water set in the wind? For now the breeze drives it hither, now the breeze of pride, now the breeze of luxury, now the breeze of envy, now the breeze of deceit drags it along. Upon the face of the water, then, he is light whom, when it comes, any wind of error drives. Whence it is well also said through the Psalmist: O my God, make them as a wheel, and as stubble before the face of the wind (Psalm lxxxii, 14). For the wicked are set as a wheel, because, sent into the circuit of labour, while they neglect the things that are before, and follow the things that are to be forsaken, they are lifted up from the hinder parts, and fall in the forward parts.
Who are also rightly compared to stubble before the face of the wind, because, when the breeze of temptation rushes in, since they are supported by no reason of gravity, they are lifted up only to fall, and often esteem themselves to be of some merit for that very reason for which the blast of error carries them into the heights. There follows: