The Maharal gives an interesting explanation as to why we add in the Birkat Hamazon the prayer, הרחמן הוא יקים את סוכת דוד הנופלת, “May the Merciful One rebuild the fallen Succah of David.”
This is based on a verse from the Book of Amos, that says, “On that day I will rebuild the fallen Succah of David.” The Maharal explains that the House of Israel, is referred to as a “Succah,” and not a “Bayit.”
The great empires of history, Babylonia, Persia, Greece, and Rome, are described as a בית. Sometimes, it could be written as בית רומי or בית בבל, the House of Rome, or the House of Babylonia. Yet, Israel is merely, the Succah.
The difference between a house and a Succah, is that when a Succah falls, it is much easier to rebuild than when a house falls. This represents the nature of the rise and fall of these empires. They begin as strong houses, but when they fall, they are not rebuilt.
But Israel’s history has been tentative and shaky, like a Sukkah. But when Israel falls, it rebuilds itself as easily as rebuilding a Succah. Israel is the only nation in all of history, that saw days of glory, that was followed by a lengthy exile, and were able to rebuild again. Witnessing the rebirth of the State of Israel, is not only miraculous, but it has never been duplicated in the history of mankind.
This is why we are referred to as a Succah, and why we pray that the Succah of David should be rebuilt.