John Trapp on Job 39:12

Verſe 12. wilt thou believe him that he will bring home thy ſeed?] That is, the crop that comes of thy ſeed: as in the former verſe, thy labour that is the fruit of thy labour, as Pſal. 128.2. There is no truſting to this wild and fierce creature to do any ſuch thing. Vertoman ſaith, that he ſaw two Unicorns, and that they were not of ſo fierce a nature, but that they might be brought to ſomewhat. But then they were not true Unicorns, ſay we: ſuch as God here deſcribeth.

And gather it into thy barn?] No truſting to the Unicorns gentleneſſe for any ſuch matter, unleſſe we deſire to be deceived.