What does Zechariah 12:9 mean?

In that day I will make the chieftains of Judah like a pan of fire among wood, and like a flaming torch among sheaves; and they will devour all the surrounding peoples, on the right hand and on the left; and Jerusalem will yet again dwell in their own place, even in Jerusalem.

Yahweh also will save the tents of Judah first, that the glory of David’s house and the glory of the inhabitants of Jerusalem not be magnified above Judah.

In that day Yahweh will defend the inhabitants of Jerusalem. He who is feeble among them at that day will be like David, and David’s house will be like God, like Yahweh’s angel before them.

I will pour on David’s house, and on the inhabitants of Jerusalem, the spirit of grace and of supplication; and they will look to me whom they have pierced; and they shall mourn for him, as one mourns for his only son, and will grieve bitterly for him, as one grieves for his firstborn.

In that day there will be a great mourning in Jerusalem, like the mourning of Hadadrimmon in the valley of Megiddon.

The land will mourn, every family apart; the family of David’s house apart, and their wives apart; the family of the house of Nathan apart, and their wives apart;