John Trapp on Zechariah 9:3

Verſe 3. And Tyrus did build her ſelf a ſtrong-hold] Thor did build her ſelf Matſor: An Elegancy not to be Engliſhed. (ſuch as are many in the old Teſtament, but eſpecially in Eſay) It is as if it ſhould be ſaid, A ſtrong hold (ſuch as Tyrus which was naturally fortified) did build it ſelf a ſtrong hold, ſc. by the induſtry and diligence of men; ſo that ſhe might ſeem impregnable: yet all ſhould not do.A Lapide. Alexander, after ſeven moneths ſiege, took it and deſtroyed it.

and heaped up ſilver as duſt] Pulverizavit argentum quaſi pulverem. Shee had money enough (by means of her long and great trade with all the world, Ezek. 27.) and ſo might hire what ſouldiers ſhe pleaſed for her defence. The ſinewes of warre were not wanting to her. She heaped up her hoards as it were to heaven: her Magazines were full fraught. The word here rendred, heapt up, ſignifieth to comport and gather in money, as men do corn into barnes and granaries. Exod. 8.10. Pſal. 39.7. But riches avail not in the day of wrath. And Tyrus converted, leaves laying up, and treaſuring, and falls to feeding, and cloathing Gods Saints, Eſay 23.18.