This Shabbat is called Shabbat Nachamu – comfort. The reason is that on this Shabbat, after the regular Torah reading, a section from the prophets is read that begins Nachamu, nachamu ami… – comfort, comfort my people… (God says to the prophets).
Immediately following the suffering of Tisha B'Av—the 9th of Av—when we fasted for the destruction of the two Temples and other tragedies, God comforts us twice over. The question arises: why do we need double comfort?
In Judaism, everything can be observed in two dimensions: the material and the spiritual. These two dimensions exist in human beings, in Divine precepts—the Mitzvot—and in buildings (such as the Temple).
True fulfillment is achieved by combining these two dimensions and bringing them to their fullest potential. A man is not merely his body, a mitzvah is not merely the action (although an action without feeling is valid as fulfilling the Divine command, but not vice versa—feeling without action), and a building is not merely its walls. There must be a soul, a feeling, a reason for being.
Therefore, being in exile, where we easily become confused and stray after what our eyes see, the material world, God sends his prophets to doubly comfort us, to teach us a basic lesson of Judaism: form (spirit) and matter must be used together in the service of God and must be complete, a fullness that we will reach with the coming of the Messiah, soon in our days.