The Gemara explains the destruction of both Temples and the many tragedies of the Ninth of Av, and develops the framework of mourning and historical meaning of the day.
בְּתִשְׁעָה בְּאָב נִגְזַר עַל אֲבוֹתֵינוּ שֶׁלֹּא יִכָּנְסוּ לָאָרֶץ, מְנָלַן — דִּכְתִיב: ״וַיְהִי בַּחֹדֶשׁ הָרִאשׁוֹן בַּשָּׁנָה הַשֵּׁנִית בְּאֶחָד לַחֹדֶשׁ הוּקַם הַמִּשְׁכָּן״. וְאָמַר מָר: שָׁנָה רִאשׁוֹנָה עָשָׂה מֹשֶׁה אֶת הַמִּשְׁכָּן, שְׁנִיָּה הֵקִים מֹשֶׁה אֶת הַמִּשְׁכָּן, וְשָׁלַח מְרַגְּלִים. וּכְתִיב: ״וַיְהִי בַּשָּׁנָה הַשֵּׁנִית בַּחֹדֶשׁ הַשֵּׁנִי בְּעֶשְׂרִים בַּחֹדֶשׁ נַעֲלָה הֶעָנָן מֵעַל מִשְׁכָּן הָעֵדֻת״. וּכְתִיב: ״וַתִּשָּׂא כׇּל הָעֵדָה וַיִּתְּנוּ אֶת קוֹלָם וַיִּבְכּוּ הָעָם בַּלַּיְלָה הַהוּא״, אָמַר רַבָּה אָמַר רַבִּי יוֹחָנָן: אוֹתוֹ לַיְלָה לֵיל תִּשְׁעָה בְּאָב הָיָה. אָמַר לָהֶם הַקָּדוֹשׁ בָּרוּךְ הוּא: אַתֶּם בְּכִיתֶם בְּכִיָּה שֶׁל חִנָּם — וַאֲנִי קוֹבֵעַ לָכֶם בְּכִיָּה לְדוֹרוֹת. חָרַב הַבַּיִת בָּרִאשׁוֹנָה, דִּכְתִיב: ״וּבַחֹדֶשׁ הַחֲמִישִׁי בְּשִׁבְעָה לַחֹדֶשׁ הִיא שְׁנַת תְּשַׁע עֶשְׂרֵה שָׁנָה לַמֶּלֶךְ נְבֻכַדְנֶאצַּר מֶלֶךְ בָּבֶל בָּא נְבוּזַרְאֲדָן רַב טַבָּחִים עֶבֶד מֶלֶךְ בָּבֶל יְרוּשָׁלִָם וַיִּשְׂרֹף אֶת בֵּית ה׳ וְגוֹ׳״, וּכְתִיב: ״וּבַחֹדֶשׁ הַחֲמִישִׁי בֶּעָשׂוֹר לַחֹדֶשׁ הִיא שְׁנַת תְּשַׁע עֶשְׂרֵה שָׁנָה לַמֶּלֶךְ נְבוּכַדְנֶאצַּר מֶלֶךְ בָּבֶל בָּא נְבוּזַרְאֲדָן רַב טַבָּחִים עָמַד לִפְנֵי מֶלֶךְ בָּבֶל בִּירוּשָׁלִָם וְגוֹ׳״. וּתְשִׁיעִי סָמוּךְ לַחֲשֵׁיכָה הֵצִיתוּ בּוֹ אֶת הָאוּר, וְהָיָה דּוֹלֵק וְהוֹלֵךְ כׇּל הַיּוֹם כּוּלּוֹ, שֶׁנֶּאֱמַר: ״אוֹי לָנוּ כִּי פָנָה הַיּוֹם כִּי יִנָּטוּ צִלְלֵי עָרֶב״. וְהַיְינוּ דְּאָמַר רַבִּי יוֹחָנָן: אִלְמָלֵי הָיִיתִי בְּאוֹתוֹ הַדּוֹר לֹא קְבַעְתִּיו אֶלָּא בָּעֲשִׂירִי, מִפְּנֵי שֶׁרוּבּוֹ שֶׁל הֵיכָל בּוֹ נִשְׂרַף. וְרַבָּנַן — אַתְחַלְתָּא דְפוּרְעֲנוּתָא עֲדִיפָא. אָמְרוּ: כְּשֶׁחָרַב בֵּית הַמִּקְדָּשׁ בָּרִאשׁוֹנָה, אוֹתוֹ הַיּוֹם תִּשְׁעָה בְּאָב הָיָה, וּמוֹצָאֵי שַׁבָּת הָיָה, וּמוֹצָאֵי שְׁבִיעִית הָיְתָה, וּמִשְׁמַרְתָּהּ שֶׁל יְהוֹיָרִיב הָיְתָה. וְהַלְּוִיִּם הָיוּ אוֹמְרִים שִׁירָה, וְעוֹמְדִין עַל דּוּכָנָם. וּמָה שִׁירָה הָיוּ אוֹמְרִים? ״וַיָּשֶׁב עֲלֵיהֶם אֶת אוֹנָם וּבְרָעָתָם יַצְמִיתֵם״, וְלֹא הִסְפִּיקוּ לוֹמַר ״יַצְמִיתֵם ה׳ אֱלֹהֵינוּ״, עַד שֶׁבָּאוּ נׇכְרִים וּכְבָשׁוּם. וְכֵן בַּשְּׁנִיָּה.
§ The mishna taught: On the Ninth of Av, it was decreed upon our ancestors that they would not enter Eretz Yisrael. The Gemara asks: From where do we derive this? As it is written: “And it came to pass in the first month in the second year, on the first day of the month, that the Tabernacle was erected” (Exodus 40:17). And the Master said: In the first year after leaving Egypt, Moses built the Tabernacle. At the beginning of the second year, Moses erected the Tabernacle and sent the spies. And it is written: “And it came to pass in the second year in the second month, on the twentieth day of the month, that the cloud was taken up from the Tabernacle of the Testimony” (Numbers 10:11). And it is further written: “And all the congregation lifted up their voice and cried and the people wept that night” (Numbers 14:1). Rabba said that Rabbi Yoḥanan said: That night was the night of the Ninth of Av. The Holy One, Blessed be He, said to them: You wept needlessly that night, and I will therefore establish for you a true tragedy over which there will be weeping in future generations. § The mishna further taught that on the Ninth of Av the Temple was destroyed the first time. The Gemara explains that this is as it is written: “And in the fifth month, on the seventh day of the month, which was the nineteenth year of King Nebuchadnezzar, king of Babylon, Nebuzaradan, captain of the guard, a servant of the King of Babylon, came to Jerusalem. And he burnt the house of the Lord” (II Kings 25:8–9). And it is also written: “And in the fifth month, on the tenth day of the month, which was the nineteenth year of King Nebuchadnezzar, king of Babylon, Nebuzaradan, captain of the guard, who served the king of Babylon, came into Jerusalem. And he burnt the house of the Lord” (Jeremiah 52:12–13). And on the ninth, adjacent to nightfall, they set fire to it, and it continuously burned the entire day, as it is stated: “Woe unto us, for the day has declined, for the shadows of the evening are stretched out” (Jeremiah 6:4). This verse is interpreted as a prophecy about the evening when the Temple was burned. And this is what Rabbi Yoḥanan meant when he said: Had I been alive in that generation, I would have established the fast only on the tenth of Av because most of the Sanctuary was burned on that day. And the Sages, who established the fast on the ninth, how do they respond to that comment? They maintain that it is preferable to mark the beginning of the tragedy. The Sages said: When the Temple was destroyed for the first time, that day was the Ninth of Av; and it was the conclusion of Shabbat; and it was the year after a Sabbatical Year; and it was the week of the priestly watch of Jehoiarib; and the Levites were singing the song and standing on their platform. And what song were they singing? They were singing the verse: “And He brought upon them their own iniquity, and He will cut them off in their own evil” (Psalms 94:23). And they did not manage to recite the end of the verse: “The Lord our God will cut them off,” before gentiles came and conquered them. And likewise, the same happened when the Second Temple was destroyed.