Hast thou with him spread out the sky, [which is] strong, [and] as a molten looking glass?
Ver. 18. Hast thou with him spread out the sky] He had convinced Job of his ignorance, and now he will of his impotence and imbecility; and this by an irony; q.d. Tune ille gigas es? Art thou indeed that giant, or demi-god, that helped the Almighty when he spread the heavens, when he laid the foundation of the earth? &c. Age itaque si tantus vires, quantum te ostentas, &c., Go to, then, if thou be indeed such a one as thou wouldst seem to be, while thou takest upon thee to be, viz. to contend with God, and to complain of his hard dealing with thee. "Teach us what we shall say unto him," &c., as Job 37:19, for we dare not, as thou hast done, dare him to come into the lists with us, as hoping to have the better of him.
Which is strong] Not by reason of any hard massy elemental thickness, but by reason of their airy, incorruptible, indissoluble nature, composed of very thin and even parts (Diodati). Hence the Greeks call it στερεωμα, and the Latins firmamentum. See Trapp on " Gen 1:7 "
And as a molten looking glass?] Perspicuum et sapphirinum, dear and transparent as a mirror wherein God maketh himself visible, as it were; who of himself is too subtile for sight or sinew to seize upon (R. Levi). The Hebrew hath it, which is strong as a molten looking glass; i.e. as a polished brazen looking glass, being more solid than brass, more transparent than crystal.