John Trapp on Job 38:18

Verſe 18. Haſt thou perceived the breadth of the earth?] Heb. The bredths, i. e. the length alſo and circumference thereof. Geographers define the length of the earth from Eaſt to Weſt, the bredth from North to South; and they have their ſupputations and conjectures.Frigidae ſunt et leves conjecturae. Mercer. Pencer, and others, tell us, that if there were a path made round the earth, an able foot-man might eaſily go it in 900. dayes. Which if he could, yet what mortal man, though he ſhould live 900. years, could ever viſit and view the whole face, nature, and dimenſion of the earth, wherein are ſo many deſerts and bogs unpaſſable? Or, what Job can give a reaſon why God made the earth of ſuch a length and bredth, and no more, when he could ſo eaſily have done it? How much leſſe can he of Gods ſecret and unſearchable judgements? and why ſhould he ſo deſire to know the cauſe wherefore he is Afflicted?

Declare if thou knoweſt it all] Sith a great part of it is uninhabited: and the ſea ſurroundeth it as a girdle.