Rashi: It is gathered - the water does not leave its place. So Ninveh was serene, and not dislocated.

Radak: It was full of all good, like a pool is full of water. Rain or spring water is gathered into a pool.

Malbim: Since the Chidekel river flooded it, it became like a pool full of water.

Rashi: From when it was made.

Radak citing Targum Yonasan: From days of old.

Malbim: The river constantly flooded it. Mahari writes that it was always full of water, and they needed to build their houses on the second story.

Rashi: Now, amidst their great pressure, they learned to flee.

Radak: They fled from it when it was captured.

Malbim: Even though the river constantly flooded it, since the diviners gave a sign, all the residents fled.

Rashi: They (Radak - the captors) tell them to stop, and no one clears his heart to listen and stop. Malbim - chronicles say that the enemy told the residents not to flee, for they came only to lower the lowlife sd44, but the residents did not listen. They fled, and no one chased them.