Four rabbis were walking away from the ruins of Jerusalem. When they reached Mount Scopus and saw the destroyed Temple, they tore their garments. When they arrived at the Temple Mount itself, they saw a fox trotting out of the place where the Holy of Holies had once stood.
Three of them—Rabban Gamliel, Rabbi Elazar ben Azariah, and Rabbi Yehoshua—began to weep. Rabbi Akiva laughed.
They turned on him. "Why are you laughing?"
He turned it back. "Why are you weeping?"
"This is the place about which the Torah says, 'The non-priest who approaches shall die' (Numbers 1:51). Now foxes walk through it. How can we not weep?"
Rabbi Akiva said: "That is exactly why I am laughing."
He explained. The prophet Isaiah linked two prophecies together (Isaiah 8:2): one from Uriah, who prophesied during the First Temple period, and one from Zechariah, who prophesied after the return from Babylon. Uriah's prophecy was destruction: "Zion shall be plowed as a field, and Jerusalem shall become rubble, and the Temple Mount as the high places of a forest" (Micah 3:12). Zechariah's prophecy was redemption: "There shall yet be elderly men and elderly women sitting in the streets of Jerusalem" (Zechariah 8:4).
The two prophecies were bound together. If one came true, the other must also come true. "Until Uriah's prophecy was fulfilled," Rabbi Akiva said, "I was afraid Zechariah's prophecy might not be fulfilled. Now that I have seen Uriah's prophecy fulfilled with my own eyes—foxes walking through the Holy of Holies—I know with certainty that Zechariah's prophecy will also be fulfilled."
The Talmud in Tractate Makkot records their response: "Akiva, you have comforted us. Akiva, you have comforted us." They said it twice. The destruction was the proof of the redemption.