In many shuls it’s customary to say yotzrot (special poems added to the morning prayers) on the Shabbatot of the Four Parshiyot. On the Shabbat Hafsakah, however, there are no special yotzrot. According to Rabbi Yitzchak Meir Morgenstern, this silence (from the readings of the special maftir as well as from the yotzrot) represents a loftier level than the levels expressed by those readings (as this level is too lofty to express in words).
Time to Think
According to the second Gerrer Rebbe (known as the Chiddushei HaRim), the purpose of the Shabbat Hafsakah is that we pause to think about the lessons of the readings of the previous Shabbat (or Shabbatot) and integrate those lessons into our hearts and lives. This is based on the teaching of our sages that the purpose of a pause in between the parshiyot (paragraphs of the Torah) was for Moshe to think about what he learned before continuing on to the next topic.
This is also why there are more spaces in the Torah scroll by the song of the sea (as well as by all of the songs of the Torah) because after a miracle one needs to take time to think about what occurred and take a lesson from it before moving on to the next matter. Whereas the section at the beginning of the Egyptian exile (Parshat Vayechi) has no space because at a time of Divine concealment it’s difficult to think deeply into the lessons of the things happening around us.
Like Rav Zeira’s Fasts
The Talmud says that, when moving to the land of Israel, Rav Zeira fasted 100 times to forget the Babylonian Talmud so that he would be able to comprehend the (much deeper) Jerusalem Talmud. The Lubavitcher Rebbe explains that this can be understood to mean that Rav Zeira fasted 100 days while focusing on achieving the methods of study of the Jerusalem Talmud. During this time he wasn’t studying with the methodology of the Babylonian Talmud nor had he yet mastered the methodology of the Jerusalem Talmud. As such it was considered as if he had “forgotten” the Babylonian Talmud despite the fact that this was a preparation to achieve a much higher level. This is similar to the time that Moshe spent reviewing the previous topic in Torah before moving on to the next one. The Shabbat Hafsakah, during which we integrate one lesson and prepare for the next, is a similar concept.
