One post shall run to meet another, and one messenger to meet another, to shew the king of Babylon that his city is taken at one end, One post shall run to meet another ... to show the king of Babylon that his city is taken at one end - (note, Jeremiah 50:24, "Thou art also taken, O Babylon, and thou wast not aware").
One post - one courier after another shall announce the capture of the city. The couriers despatched from the walls who Cyrus enters shall "meet" those sent by the king. Their confused running to and fro would result from the sudden panic at the entrance of Cyrus into the city, which he had so long besieged ineffectually: the Babylonians had laughed at his attempts, and were feasting at the time without fear.
Taken at one end - which was not known for a long time to the king and his courtiers feasting in the middle of the city: so great was its extent that, when the city was already three days in the enemy's hands, the fact was not known in some parts of the city (Aristotle, 'Polemics,' 3: 2).