Jamieson, Fausset and Brown on Job 6:4

4. arrows ... within me--have pierced me. A poetic image representing the avenging Almighty armed with bow and arrows (Psa 38:2, 3). Here the arrows are poisoned. Peculiarly appropriate, in reference to the burning pains which penetrated, like poison, into the inmost parts--("spirit"; as contrasted with mere surface flesh wounds) of Job's body.

set themselves in array--a military image (Jud 20:33). All the terrors which the divine wrath can muster are set in array against me (Is 42:13).