Verse 5. — Others, like wild asses in the desert, go forth to their work. 60. Heretics are like wild asses. They do not accomplish God's work, but their own. — For the wild ass (onager) is a wild ass of the fields. And rightly are heretics here compared to wild asses, because, given over to their own pleasures, they are strangers to the ways of faith and of reason. Whence it is written: A wild ass accustomed to the wilderness, in the desire of his soul drew in the wind of his love (Jeremiah 2:24). The wild ass indeed is accustomed to the wilderness, because while he does not cultivate the ground of his heart by the power of discipline, he dwells there where there is no fruit.
Because in the desire of his soul he draws in the wind of his love, in that the things which he conceives in his mind from the desire of knowledge prevail to puff up, not to build up. Against whom it is said: Knowledge puffs up, but charity builds up (1 Corinthians 8:1). Whence here also it is fittingly inferred: They go forth to their work. For they accomplish not God's work, but their own, while they follow not right doctrines, but their own desires. For it is written: He that walked in the unspotted way, he ministered to me (Psalm 100:6). He, therefore, who walks not in the unspotted way, ministers to himself rather than to the Lord. There follows: