What does Zechariah 6:15 mean?

People from far away will come and help build the Lord’s temple. You’ll know the Lord of all sent me to you when this happens. But this will only happen if you really listen to the Lord your God. Zechariah 6:15 - Modern Text Bible

(God promises that outsiders will join in rebuilding the temple, confirming Zechariah’s message. But this promise depends on the people’s willingness to truly listen and obey God.)