This day the Ninth of Av (30 July 2009) is not a memorial given by God. It is a Jewish day for mourning the evil of the sudden absence of God that came with the destruction of the Temple (twice, on the same date, the Ninth of Av, 660 years apart), and 65 years later on the same date, in 135AD the destruction of the last Jewish fortress of the Bar Kochba revolt from Rome, after 3 years of Jewish independence in the Holy Land.
The conjunction of these events was enough to cause the ancient scholars to declare it a date of mourning. They also noted on that day the nation of the Israelites were condemned for their lack of faith when the 12 spies reported back to Moses regarding the Promised Land.
If this was not enough, more modern history records the day as one of loss and suffering also. On that day Jews were expelled from England in 1290, from Spain in 1492 (the decree took effect on the 7th of Av), and on the eve of that day in 1942 all Jews were deported from the Warsaw Ghetto.
All the events are one. The loss of the Temple was physical evidence of the loss of the protective blessing of Yahweh the God of Israel, as was the expulsion and persecution. It is worthy for all to ponder that the events are dramatic evidence of the covenant made with Israel in the days of Moses,
all the nations shall say, “Why has Yahweh done thus to this land? What does the heat of this great anger mean?”
Then men shall say, “Because they forsook the covenant of Yahweh, the God of their fathers, which he made with them when he brought them forth out of the land of Egypt, (Deuteronomy 29:24-25)
The covenant with Yahweh in the days of Moses came with a blessing and a curse,
I call heaven and earth to witness against you this day, that I have set before you life and death, the blessing and the curse: therefore choose life, that you may live (Deut. 30:19)
Moses knew that, just as the blessing would come, so would the curse,
It shall happen, when all these things have come on you, the blessing and the curse, which I have set before you, and you shall call them to mind among all the nations, where Yahweh your God has driven you, and shall return.. and shall obey his voice according to all that I command you this day..., with all your heart, and with all your soul; that then Yahweh your God will turn your captivity, and have compassion on you, and will return and gather you from all the peoples, where Yahweh your God has scattered you.(Deut. 30:1-3)
Whereas the covenant is perpetual, the blessing of God is a conditional part of that covenant. The covenant proclaims that God would bring the Jews back to their land, if they repented. They were brought back after the destruction of the first temple, and some came back briefly after the destruction of the second temple. The mourning that occurs as a memorial on Tisha B'Av is similar to the day of Atonement, where people repent.
So why is Tisha B'Av still a day of mourning if the Jews are returned to the land? Because the temple, and the presence of the God of Israel on earth, is still absent.
There is an important link between exile, suffering and seeking the temple. Jonah in deep trouble cried,
I said, ‘I have been banished from your sight; yet I will look again toward your holy temple.’
“When my soul fainted within me, I remembered Yahweh. My prayer came in to you, into your holy temple.(Jon 2:4,7)
David puts it like this,
In my distress I called on Yahweh. Yes, I called to my God. He heard my voice out of his temple. My cry came into his ears.(2 Samuel 22:7)
The Jews in remembering Tisha B'Av show us that until the temple is built and Messiah comes, God is absent. We may mistake the matter if today we think we are not in an era of exile. God is not with us now as he was with Israel when the temple was in existence. At time when the second temple was about to be lost, the writer to the Hebrews points out that Abraham, Isaac and Jacob were commended for calling themselves 'strangers' (Hebrews 11:13).
The power of the Absent Temple
Jonah and David when in trouble prayed towards the temple. Due to Solomon even the place of the absent temple has power. This is what Solomon asked of God regarding his temple,
If they sin against you (for there is no man who doesn’t sin), and you are angry with them, and deliver them to the enemy, so that they carry them away captive to the land of the enemy, far off or near; yet if they shall repent in the land where they are carried captive, and turn again, and make supplication to you in the land of those who carried them captive, saying,
‘We have sinned, and have done perversely; we have dealt wickedly;’if they return to you with all their heart and with all their soul in the land of their enemies.., and pray to you toward their land, which you gave to their fathers, the city which you have chosen, and the house which I have built for your name:
then hear their prayer and their supplication in heaven, your dwelling place, and maintain their cause; and forgive your people who have sinned against you, and all their transgressions in which they have transgressed against you; and give them compassion before those who carried them captive, that they may have compassion on them (1Kings 8:46-50)
The prayer was confirmed see Solomon's Prayer
According to Wikipedia
Orthodox Jews believe that until the arrival of the Jewish Messiah, this day will continue to be observed as a fast; when the Messiah and the rebuilding of the Temple come, it will become a great celebration. This notion is asserted on the basis of a passage in the Book of Zechariah (8:19) that foretells of the transformation of four fast days into joyous holidays.
Thus says Yahweh of Armies: “The fasts of the fourth fifth, seventh, and tenth months shall be for the house of Judah joy and gladness, and cheerful feasts. Therefore love truth and peace.”(Zechariah 8:19)
Zechariah then goes on to write,
Thus says Yahweh of Armies: “Many peoples, and the inhabitants of many cities..Yes, many peoples and strong nations will come to seek Yahweh of Armies in Jerusalem, and to entreat the favor of Yahweh.” Thus says Yahweh of Armies: “In those days, ten men will take hold, out of all the languages of the nations, they will take hold of the robe of him who is a Jew, saying, ‘We will go with you, for we have heard that God is with you.’”(Zechariah 8:20-23)
Jesus (Hebrew Yeshua) put it another way, when he would not allow anyone to carry a container through the temple,
He taught, saying to them, “Isn’t it written, ‘My house will be called a house of prayer for all the nations?’ But you have made it a den of robbers!”(Mark 11:16-17)
Yeshua is quoting Isaiah, who said that the temple in the future would be a house of prayer for all nations. This was while the first temple was still in existence (Isaiah56:7). Yeshua also spoke in the future tense while the second temple was in existence. Neither temple was the house of prayer for all nations.
The Ninth of Av- Tisha B'Av, is to remember the absence of the temple. But from Isaiah we know that this absence relates all people on earth. There is not yet, and has never been, a temple of God that is “the house of prayer for all nations”. On that day mourning will become rejoicing.
For more on the temple The City The Holy
And The house of God