Jamieson, Fausset and Brown on Zechariah 9:5

5. Ashkelon, &c.--Gath alone is omitted, perhaps as being somewhat inland, and so out of the route of the advancing conqueror.

Ekron ... expectation ... ashamed--Ekron, the farthest north of the Philistine cities, had expected Tyre would withstand Alexander, and so check his progress southward through Philistia to Egypt. This hope being confounded ("put to shame"), Ekron shall "fear."

king shall perish from Gaza--Its government shall be overthrown. In literal fulfilment of this prophecy, after a two month's siege, Gaza was taken by Alexander, ten thousand of its inhabitants slain, and the rest sold as slaves. Betis the satrap, or petty "king," was bound to a chariot by thongs thrust through the soles of his feet, and dragged round the city.