Chapter 12

Titled "The Lord Will Give Salvation" in the ESV.

This begins talking about "that day".  Seems to me, from vss 1-5, that this is a reference to the battle between the forces of Antichrist and Jesus immediately preceding establishment of the Millennial Kingdom.  This battle will be over, I believe, in only minutes, as Jesus himself will do the fighting.  Antichrist - the human part - will be killed, and the beast and false prophet thrown into the pit.  What will happen will be so "unearthly" that the whole world will know, and recognize, and no longer have any doubt, that there is a God in Israel.  This seems to confirm it:

9 And on that day I will seek to destroy all the nations that come against Jerusalem. [Zec 12:9 ESV]

2026 - Today, I don't see this as the battle before the Millennial.  That battle is at Megiddo.  What is in view here in these first verses of 12 is a siege of Jerusalem.  We know that happens is 70 AD.  Was Zech talking about a siege in his own time?  When would that have been?  I don't know that Jerusalem was ever under siege from Zech's time to 70 AD. 

These next verses speak to the restoration of the Sinai covenant.  As is the case with grace, it will be God who initiates, God who makes

His chosen able to receive what He offers.  In our sin and corruption, we are not capable of seeing the decision before us.  We haven't got the ability to choose the right way.  This is the whole point in all creation - from angels to Israel.  There is none righteous, no not one!  Only God can give us the insight to choose Him.  And that is what is going to happen as the Millennial opens.  This is how restoration of the covenant will come about.  Those who were blinded will be able to see, and they will finally keep the promises they made at the mountain.  Here:

10 "And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and pleas for mercy, so that, when they look on me, on him whom they have pierced, they shall mourn for him, as one mourns for an only child, and weep bitterly over him, as one weeps over a firstborn. [Zec 12:10 ESV]  A national revival.  None will be skipped.  All Jews, where ever they are, will know that Jesus was the Christ they had awaited.

Hadad-Rimmon is the place where King Josiah was killed.  That's why the mourning there was so great.  So interesting that he was killed on the plain of Megiddo.