Now Nineveh was... — The past tense here certainly seems to imply that at the time in which the author wrote the city was no longer in existence, but the force of a Hebrew tense is not to be estimated by the analogy of modern languages.
An exceeding great city. — Literally, A city great to God; an expression equivalent to a divinely great city, and taken, as Ewald thinks, from the language of the people, like the Arabic “to Allah,” in the saying “to Allah (i.e., divine) is he that composed this.” In the Hebrew poetic and prophetic writings a finer form is found, e.g., “mountains of God,” “cedars of God” (Psalms 36:6; Psalms 80:10), “trees of Jehovah” (Psalms 104:16), but in Genesis 10:9 a precisely similar proverbial use shows itself, also belonging to the Mesopotamian region, “Nimrod, a mighty hunter before the Lord.”
Of three days’ journey. — Hitzig takes this as giving the diameter of the city, but most commentators refer it to the circumference. The circuit of the walls was the most obvious measurement to give of an ancient city. Herodotus variously reckons a day’s journey at about eighteen or twenty-three miles (v. 53, iv. 101), and the circuit of the irregular quadrangle composed of the mounds of Koujunjik, Nimrud, Karamless, and Khorsabad, now generally allowed to represent ancient Nineveh, is about sixty miles. This agrees sufficiently with the obviously vague and general statement of the text.