12 God will smite the people who fought against Jerusalem with a plague. Their flesh will rot away while they are standing, their eyes will rot in their sockets, and tongues will rot in their mouths.
And all the Canaanites will be removed from God's house.
A few more words about this episode
Thy King cometh ... riding upon an ass, and upon a colt the foal of an ass. (9:9)
The author of the gospel of Matthew (Mt 21:5) quoted this verse, claiming that Jesus fulfilled it when he entered Jerusalem. But he interpreted it a bit too literally, saying that Jesus rode on a colt and and ass at the same time.
The author of John's gospel dropped the colt and went with the ass. Jn 12:15
Thirty pieces of silver (11:12-13)
The gospel of Matthew claims that this passage was fulfilled when the priests bought the potter's field with the money they paid Judah, after he refused to take the money. But the author messed it up a bit by attributing it to Jeremiah rather than Zechariah. (Mt 27:3-10)
They will look upon the one whom they have pierced (12:10)
This verse is claimed to have been fulfilled by Jesus's crucifixion. (Jn 19:37)
God will kill the shepherd, scatter the sheep, and kill the little ones. (13:7)
Jesus, in the gospel of Matthew, attributes this verse to himself. (Mt 26:31)
So I guess Jesus thought that God was going to kill him and then slaughter his followers.
On that day (14:7)
The phrase "on that day" ("in that day" in the KJV) is used 20 times in the book of Zechariah, 18 times in the last six chapters. It isn't clear what the author had in mind, but many Christians believe it to refers to the end of the world.