And I will pour on the house of David and on the inhabitants of Jerusalem the Spirit of grace and supplication; then they will look upon me whom they have pierced. Yes ,they will mourn for him as one mourns for his only son, and grieve for a firstborn.
In that day there shall be great mourning in Jerusalem, like the mourning at Hadad Rimmon in the plain of Megiddo….

In that day a fountain shall be opened for the house of David and for the inhabitants of Jerusalem, for sin and for uncleanness.

It shall be in that day, says the Lord of hosts, thatI will cut off the names of idols from the land, and they shall no longer be remembered. I will cause the prophets and the unclean spirit to depart from the land.
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If this is a literal event , has it already occured in Jerusalem (in which case : what is the evidence?) or shalll we be aware it is coming?

The verse you quoted above is from Zechariah, chapter 12. If you were to read the entire passage in context, at the very least, chapter 12 and 13, in their entirety, you would begin to see the complete picture from which you have excised these few verses. It is clear that this “event” has not yet happened. Some evidence that it has not happened yet?

12:3 says that all the peoples of the earth will be gathered against Jerusalem.

12:4 says that in that day, G-d would strike every horse with “astonishment” (whatever that means), every rider with madness, and every horse of the nations with blindness.

12:6 says that G-d will give, in that day, the Leaders of Judah an incredible passion and power, and they will destroy “peoples round about” and that the Jewish people will inhabit the Land, including Jerusalem.

12:9 indicates that G-d himself will destroy all the nations that come against Israel.

The last few verses of chapter 12 indicate a great mourning among all the people in the Land of Israel.

13:2 Indicates that G-d will rid the land of all idol worship

13:8 indicates that 2/3 of the inhabitants of the Land will die.

Now, even though a few of these things are similar to events that have already occurred in history – for example, there are Jews now living in the land – the truth is, that this passage indicates that all of these things will occur at this particular time in history, which has clearly not happened yet.

Christianity has historically been fascinated with any verses in the Hebrew Scriptures which make reference to someone being “pierced” because they are believed to lend credibility to the idea that Jesus fulfilled Jewish prophecy. This has even led to the mistranslation of a verse in Psalms by Christian translators (that I will not get into here). However, upon close examination, it is clear that while this passage may be a prophecy pertaining to messianic times, it clearly does not refer to Jesus.

Using only an English translation of this verse could render it difficult to understand. However, when it is read in the original Hebrew, with its particular usages, it becomes clear.

Taking the verse apart in the Hebrew, we understand the verse as follows:

THEY - the Nation of Israel, i.e., the house of David and the inhabitants of Jerusalem, mentioned at the beginning of verse 10

SHALL LOOK TO ME - God

WHOM THEY - That is, the nations, spoke of in verse 9, that shall come up against Jerusalem

HAVE PIERCED - When Israel, the apple of G-d�s eye is attacked, G-d Himself feels as though He has been attacked. This is supported by several verses in the Hebrew Scriptures. (See Is 63:9, Jer 12:14, Is 49:25, Ex 23:22, Zech 2:12-13)

THEN THEY - Israel

SHALL MOURN FOR HIM - The slain of Israel

According to Gerry Sigal, in his book, The Jew and the Christian Missionary,

“Christian missionaries, in their confusion, equate the “Me” with the “him” of verse 10 and refer both to Jesus. Grammatically, the “Me” and the “him” cannot refer to the same individual. The only admissible interpretation is that the Gentile nations shall look to God, whom they have attacked by the persecution, death, and general suffering they inflicted on the nation of Israel (“him”), whose dead will be mourned by the surviving Jewish people. The rabbis of the Talmud saw this suffering personified in the leader of the people, the warrior Messiah, the son of Joseph, who will be slain at this time (B.T. Sukkah 52a). All of the nation’s dead will be mourned, but the mourning over the death of the warrior Messiah symbolizes the collective grief as the people mourn for the fallen of Israel. The author of the Gospel of John realized the untenability of the claim that Zechariah’s prophecy referred to Jesus. John, perplexed by Zechariah’s prophecy, changed the wording of verse 10 to make it conform to his belief. Thus, he wrote, “They shall look upon him (not “Me” as in the Hebrew text) whom they have pierced” (John 19:37). Emending a text may be a convenient way of demonstrating one’s theological beliefs, but has nothing to do with biblical authenticity.”