"Joy unspeakable and full of glory"

I love how the Old Testament seems to have more and more joyful passages the closer the Biblical timeline gets to the birth of Christ. Consider that all of these passages were written either during the decline of Judah or after the Babylonians destroyed the kingdom:
"Sing, O daughter of Zion; shout, O Israel; be glad, and rejoice with all the heart, O daughter of Jerusalem. The Lord hath taken away thy judgments, he hath cast out thine enemy: the king of Israel, even the Lord, is in the midst of thee: thou shalt not see evil any more. In that day it shall be said to Jerusalem, Fear thou not: and to Zion, Let not thine hands be slack. The Lord thy God in the midst of thee is mighty; He will save, he will rejoice over thee with joy; he will rest in his love, he will joy over thee with singing." --Zephaniah 3:14-17
"Sing and rejoice, O daughter of Zion: for lot, I come, and I will dwell in the midst of thee, saith the Lord. And many nations shall be joined to the Lord in that day, and shall be my people: and I will dwell in the midst of thee, and thou shalt know that the Lord of hosts hath sent me unto thee. And the Lord shall inherit Judah his portion in the holy land, and shall choose Jerusalem again. Be silent, O all flesh, before the Lord: for he is raised up out of his holy mountain." --Zechariah 2:10-13
"Rejoice greatly, O daughter of Zion; shout, O daughter of Jerusalem: behold, thy King cometh unto thee: he is just, and having salvation; lowly, and riding upon an ass, and upon a colt the foal of an ass." --Zechariah 9:9
"And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn."
--Zechariah 12:10
If the prophets could be this joyful during a time of decay and destruction, then we have no excuse but to imitate them. Now, don't get me wrong: I am not talking about some sort of Pollyanna-like "glad game" really. Rather, we should be joyful in the fact that Christ has come and saved us eternally. In fact, we actually have even more reason than Zephaniah or Zechariah or any of the other prophets had to be joyful, because that which they saw dimly in the future we now see in the light of the present day. Anyway, I think it fitting to put in a happier post since my last posts have been rather--shall we say--gloomy.
P.S. Zechariah 12:10 (the last passage listed above) is a very intriguing verse of Scripture to me. It prophesies that the Jews will mourn for Him Whom they have pierced (a phrase which points almost explicitly to Jesus Christ). Although I believe this verse was partially fulfilled on the Day of Pentecost when Peter preached to his brethren, I also wonder if it points to a future time yet to be seen when a glorious Christian revival will sweep across the Jewish people. As Paul said in Romans 11:5, "Even so then at this present time also there is a remnant [among the Jews] according to the election of grace." How awesome it would be to see that day, if that is indeed the day to which these verses--one in the Old Testament, one in the New--refer.
P.P.S. Another element common to all of these Old Testament verses is that of singing. The concept of singing to the Lord is seen throughout the Bible as an integral part of worshiping God, alongside prayer. Moreover, my personal belief is that we should sing to Him using the purest instrument in existence: the voice, the only instrument designed by God Himself.