"...In his commentary on the Mishna, Maimonides attributes equal weight to the study of Hebrew and to the joy we must feel on the Festivals - and even to the mitzvah of circumcision..."
The sages teach: "In the End of Days the Almighty will transform the Ninth of Av into joy and happiness . . . and He will Himself rebuild Jerusalem and gather in the exiles, as it is written, "He builds Jerusalem, gathers in the outcasts of Israel."