So Jonah arose, and went unto Nineveh, according to the word of the LORD. Now Nineveh was an exceedingly great city of three days' journey around it.
All Commentaries on Jonah 3:3 Go To Jonah 3
George Leo Haydock
AD 1849
Journey. By the computation of some ancient historians, Ninive was about fifty miles round: so that to go through all the chief streets and public places, was three days' journey. (Challoner)
Diodorus (iii. 1.) says Ninive was 150 stadia or furlongs in length. It must have been therefore 480 round; and as each furlong contains 125 paces of 5 ft. each, the compass would be "60 Italian miles, (about 50 English) "which would employ a person three days to go through the principal streets. (Worthington)
Ninive "was much larger that Babylon. "(Strabo xvi.)
Hebrew, "a great city of God", denoting its stupendous size.