The Shev D'Nechemta - The Seven Haftaros of Consolation
On the Shabbos immediately after Tisha B'Av, we read the haftara of "Nachamu, nachamu" from Yeshayahu. Each consecutive Shabbos, until Rosh Hashana, we read another selection from Yeshayahu, in which the prophet continues to comfort the Jewish People, following the destruction of Yerushalayim and the dispersion of our people from our Land. Each selection elaborates upon the future restoration of B'nei Yisroel and the renewed glory of Hashem as perceived in this world. This string of haftaros is termed the "Shev D'Nechemta" - the Seven (Haftaros) of Consolation.
It iwould be understandable to read one haftara of consolation after Tisha B'Av. Why, however, do we read a whole series of haftaros of consolation for seven straight weeks, all the way up to the month of Tishrei?
I think that the answer is rooted in the basics of Rosh Hashana. Unlike any other time, Rosh Hashana is marked as the day when we proclaim Hashem's ultimate and unparalleled Malchus (Kingship). On Rosh Hashana, we not only affirm our belief in Hashem's Malchus, but we coronate Hashem as our King and reconnect to Him as His loyal subjects.
Contrasted with this state of affairs is Tisha B'Av, when human perception of Hashem's glory in this world is stifled, as His House (the Beis Ha-Mikdash) is utterly destroyed, His people is exiled, and His Land is forsaken. Kabbalistically, the present situation is termed "Galusa De'Shechinta" - "the exile of God's Presence".
In order to progress from the depths of Tisha B'Av to full realization of Hashem's manifest malchus on Rosh Hashana, we read the Shev D'Nechemta, as we reconnect to Hashem's Kingship and attain the greatest appreciation of it in preparation for the ultimate day of Malchus. It is not simple to go from the Galusa De-Shechinta of Tisha B'Av, when Hashem's Presence is largely hidden, to Chodesh Elul and Rosh Hashana, when we declare and celebrate the conspicuous Malchus of Hashem. We need to gradually progress from one stage to the next. The Haftaros of Consolation enable us to approach Rosh Hashana and relate to Hashem's manifest Malchus as we should.
The haftara of Shabbos Nachamu powerfully begins the period of reawakening to Hashem's kingship, culminating in its fully glory on Rosh Hashana.