This is a very short chapter. I believe it speaks of the millennial period in the spiritual sense, and of Christ’s and John the Baptist’s ministries in the physical sense.
Verse one talks of a fountain being opened up to the inhabitants of Jerusalem for sin and uncleanliness. We saw a river flowing out of the Temple in Revelation 22, lined by healing trees. Also, John the Baptist baptized people in the Jordan as a sign of repentance from sin and cleanliness.
All workers of evil will be cut off. This happens on Christ’s return in Revelation.
The Shepherd will be struck and the sheep will scatter. This happened when the disciples scattered when Christ was arrested. In Revelation 11, there are also two witnesses who are foretold to be crucified in much the same way as Christ. This would be a time that anyone following these two witnesses who did not know the scriptures could also lose hope and scatter.
One third of believers will brought through a cleansing fire to purify them. I do not know how this compares to Christ’s crucifixion and resurrection. This event was told of by ancient prophets such as Ezekiel and Daniel. I think people connect it to how Judah would be conquered by Babylon, but that doesn’t make sense. That could be true of Ezekiel, who prophesied just before Judah was conquered. But Daniel prophesied these things during the time of Darius, over seventy years after being captured, and after the Babylonians themselves were defeated by the Persians. Zechariah also prophesies in the time of Darius, after the captured Israelites have already returned to Israel. These prophesies cannot speak of Babylonian capture, but some later date.
Here are the specific references I’m pointing to in Ezekiel and Daniel:
And you, son of man, take a sharp knife, take a barber's razor, and cause it to pass upon your head and upon your beard: then take balances to weigh, and divide the hair. You shall burn a third part with fire in the midst of the city, when the days of the siege are fulfilled: and you shalt take a third part, and slash about it with a knife: and a third part you shalt scatter in the wind; and I will draw out a sword after them. You shalt also take from it a few in number, and bind them in your skirts. Then take of them again, and cast them into the midst of the fire, and burn them in the fire; for thereof shall a fire come forth into all the house of Israel.
And they that understand among the people shall instruct many: yet they shall fall by the sword, and by flame, by captivity, and by spoil, many days. Now when they shall fall, they shall be helped with a little help: but many shall cleave to them with flatteries. And some of them of understanding shall fall, to try them, and to purge, and to make them white, even to the time of the end: because it is yet for a time appointed.
What a challenge and an honour to see such times. Praise God in all things. (I need a constant reminder of this.)