When our ancestors left Egypt G-d provided them with a miraculous “pillar of cloud by day to guide them along the way, and a pillar of fire by night to give them light” (Exodus 13:21) which have come to be known as The Clouds of Glory. As Ramchal explains it, the sukkah we sit in on Sukkot alludes to them.
Now, there are certain undeniable metaphysical implications to The Clouds of Glory as well (as we’ll soon see), but on a human-level they exemplify G- d’s loving comfort and guidance. After all, G-d does indeed love us; and besides escorting us throughout the day and night, His presence likewise hovers over us lovingly and bounteously like a rain cloud on a dry summer day. And that’s an important point to recall after concentrating so intently on the notion of G-d as Judge throughout Rosh Hashanah and Yom Kippur.
But what The Clouds of Glory managed to achieve on another, deeper level was to set our people apart from their surroundings. For aside from sparing them from the harsh desert winds and sands, they also separated them from the other nations they passed through — both physically and spiritually, acting as a sort of otherworldly shield and sheath. And they also provided the venue for a unique illumination from Above that elevated our people and nourished their uniqueness.
Ramchal’s point is that that same dynamic is in effect each year, on Sukkot. The sukkah we sit in all week long serves to bear us much the way The Clouds of Glory bore our ancestors. And it too allows for a certain inchoate illumination that sets the righteous among us apart from others (as well as our more righteous side from the rest of our own beings).
The lulav (palm frond) along with its myrtle- and willow-branches, and the etrog (citon) allows for that same illumination and distinction. But it also acts as a Divine emblem or weapon of sorts to daunt and disquiet our enemies. And while the geulah (“redemption”) from oppression that’s sure to come could come about right *now*, were it not for our failings, it will eventually come — thanks to the illumination allowed by the mitzvah of lulav.
In fact, we act out that scenario the whole week long, when we shake the lulav and etrog, and march around the synagogue with them, as if encircling the world with a sort of “sukkah” of our own presence; and as if defeating the enemies of holiness. We also set the way for the great and ultimate illumination of G-d’s presence throughout the world by doing that, and ready everything and everyone for the geulah and for the service of G-d only possible then.