This angel is a new person and has not appeared before, and so should be clearly introduced as a new participant. AT: "a new angel went out to meet him:"
Yahweh is saying he will protect Jerusalem and compares his protection to a wall of fire. (See: [[rc://en/ta/man/translate/figs-metaphor]])
## this is Yahweh's declaration ##
This phrase is often translated as "Yahweh says" in the UDB. You can translate this concept whichever way is best in your language. This phrase is used many times in Zechariah.