Yahweh's Angel & Egypt's Plague

Zechariah says the house of David will be like God, like the angel of the Lord before them. A few lines later the people mourn as one mourns for a firstborn.
That is an allusion back to the last plague against Egypt, and to the figure who carried it out. In Exodus the destroyer passes through, and the sources are clear that Yahweh acted in the form of his angel, against the gods and people of Egypt.
The plagues were never only about Pharaoh. They were a judgment on Egypt's gods, executed by the angel in whom Yahweh's own presence resided.
Scripture links:
- Exodus 13-14 - the deliverance, the pillar, and the destruction of Egypt's army.
- Zechariah 12:8-10 - like God, like the angel of the Lord, and mourning as for a firstborn.
The figure who went through Egypt is the one Zechariah says will go before the house of David.