What does Zechariah 9:13 mean?

I've made Judah my bow and loaded it with Ephraim. I'll stir up your sons, Zion, against your sons, Greece, and make you like a warrior's sword. Zechariah 9:13 - Modern Text Bible

(God will empower His people to stand strong against their enemies, especially against Greece, using Judah and Ephraim together as His weapon.)