Job 6:5 - Joseph Benson’s Commentary on the Old and New Testaments

Doth the wild ass bray when he hath grass? &c. “Grass and fodder here are a figure of abundance and tranquillity, such as the friends of Job enjoyed. To bray and low refer to expressions of grief and uneasiness. Job therefore compares his friends, with some smartness, to a wild ass exulting in its food, and to an ox perfectly satisfied with grateful pasture.” His words may be paraphrased thus: Even the brute beasts, when they have convenient food, are quiet and contented. So, it is no wonder that you complain not, who live in ease and prosperity, any more than I did when I wanted nothing; “happy yourselves, you do not condole with me in my wretchedness, nor mourn with me, but rather blame my mourning as importunate clamour, and as if I had behaved myself toward God with insolence and impatience.” Schultens.