John Trapp on Job 38:3

Verſe 3. Gird up now thy loins like a man] As men did uſe to do when they went to fight, 1 King. 20.11. Stand to thy ward, and ſee to thy ſelf: for I mean to aſſail thee, and to try thy manhood. Plato hath obſerved, that the beſt Fencers are the worſt Souldiers. Many can brave it afore-hand, as that Thraſonical Gaal did, Judg. 9.29. who yet cannot look their enemy in the face with blood in their cheeks.

For I will demand of thee, and anſwer thou me] I will be thy opponent (ſith thou haſt challenged me into the ſchooles, as it were, and given me my choice) and prove thee with hard queſtions; whereunto if thou canſt give no good anſwer, ſee thine own folly, and be ſatisfied.