Albert Barnes Commentary Job 39:22

"He mocketh at fear, and is not dismayed; Neither turneth he back from the sword." — Job 39:22 (ASV)

He mocks at fear – He laughs at that which is fitted to intimidate; that is, he is not afraid.

Neither turns he back from the sword – He rushes on it without fear. Of the fact here stated, and the accuracy of the description, there can be no doubt.