because of him
There seems to be a reference here to the advance and return of Alexander (Zechariah 9:13) after the battle of Issus, who subdued the cities mentioned in (Zechariah 9:1-6); and afterward returned to Greece without harming Jerusalem. But the greater meaning converges on the yet future last days
( See Scofield) - (Acts 2:17)
as the last clause of verse (Zechariah 9:8) shows, for many oppressors have passed through Jerusalem since the days of Alexander.