Work on the succah begins immediately after Yom Kippur.  Although this custom is often understood as simply a great way to 'get off to a good start' (spiritually) it also alludes to something more significant.

Yom Kippur was the day that Moses received the second tablets, revealing YHVH's Mercy to His people.  YHVH agreed to Moses' plea that He return His shechinah to Israel, even though He had taken it away in the aftermath of the golden calf. (Ex 33:1-8)  However, the shechinah did not return immediately - only some six months later - after Israel built the Tabernacle. (Ex 25:8; Lev 9:1-5)

The first thing that Moses did after receiving the (Second) Tablets was gather the people together and charge them with the building of the Tabernacle.  Even though the shechinah would return, Israel had to do something to 'receive' it.  Just like Moses had to carve his own second  tablets, in contrast to the first tablets which YHVH Himself had carved, (Ex 34:1) in a similar manner Israel must now become more active and build the Tabernacle.

Building the succah immediately after Yom Kippur reflects this same idea.  Just as Israel began to work on the Tabernacle after Yom Kippur, we also begin building our succah where we can 'meet' the shechinah in a similar way.

Sitting in the succah symbolizes our sitting under the 'clouds of YHVH's glory' in the desert, with Yom Kippur as the preparation for Succot. 

Remembering 'What' And 'Why'

We are commanded to observe the festival of Succot not just to remember to be thankful that YHVH provided for Israel's needs while they traveled through the desert, but to remember why the entire desert experience was necessary.

Life In The Desert - A Transition Stage

"You shall sit in succot for seven days in order that your future generations may know that I made Israel dwell in succot when I brought them out of Egypt."  Lev 23:43

The entire desert experience served as a training period, to transform Israel from a nation of slaves into a model nation in the Promised Land.  This process began with the plagues, the Exodus and the splitting of Red Sea, in order to convince Israel of their total dependence upon YHVH.  That high level of miracles was more of an attention getter than an ideal.  Israel had to learn to recognize YHVH in their daily lives without the help of miracles.  This required a long educational process to prepare them for the challenges of daily existence in the Land of Israel.

"All these commandments which I command you... keep in order that you live... and inherit the Land. Remember the way that YHVH led you during your wanderings of forty years in the desert, in order to test you with hardships to know what is in your hearts; whether you would keep His commandments or not. He gave you the manna to eat... in order to teach you that man does not live on bread alone... that you should know that just as a father puts his son through hardship (to train him) so too has YHVH put you through hardship."  Deut 8:1-6

The manna served as 'training' food for Israel, to teach them that their food came from YHVH, so that when they enter the land of Israel and make their own food they will remember the source of their sustenance.

"For YHVH is bringing you into a good land... where you will lack nothing... be careful, lest you forget YHVH and fail to keep His commandments... beware lest you grow prideful and forget your Elohim who took you out of Egypt... lest you say my own power and my own might have won this wealth for me. Remember that it is YHVH your Elohim who gives you the power to get wealth."  Deut 8:7-19

YHVH was concerned that Israel will become haughty, therefore He instructed them to remember their lessons from the desert and be prepared for the spiritual dangers facing them. 

To recognize the hand of YHVH in a miracle is easy.  To recognize His hand within the process of life is a much more difficult challenge.  For this reason we are commanded to celebrate Succot on a yearly basis, not only to remember it but to virtually 're-live' the desert experience (to know it), by living for seven days in a succah.

The Most Fitting Time Of The Year

Our own life experience certainly supports the credibility of  the Torah's fears that economic affluence may lead to forgetting YHVH.  (Deut 31:16,20; 32:13-15)
 
Succot comes at the climax of the agricultural year, as we gather the fruits and count our wealth.  It is specifically during this time of year that the spiritual dangers of affluence are greatest.  Just as dwelling in the desert prepared Israel for entry into the Promised Land, so too, our sitting in the succah prepares us for the spiritual challenges that surface as we reflect on our wealth.   

'Knowing' - Biblical Intimacy

To 'know' something (or someone) in the Bible means much more than intellectual knowledge and implies close and very intense relationship. 

The Torah uses the phrase "to know" to describe the intimate relationship between husband and wife.  (Gen 4:1)  It is not by chance that this word is used to describe the Tree of Knowledge in the story of the Garden of Eden.  Later on, when YHVH takes a close look at the people of Sodom - to punish them for their terrible sins - the same verb 'to know' is used. (Gen 18:21)  At the time of the Exodus we find this same intense relationship between YHVH and Israel, making sure that Israel 'knows' that YHVH is their deliverer.

"I am YHVH and I will take them out and save them, and redeem them with an outstretched hand... and take them as My nation and I will be their Elohim In order that they will know that I am YHVH who has taken them out of Egypt."  Ex 6:6-7

We are commanded to sit in the succah to know and totally identify with the purpose of that 'desert experience' and its eternal message - that man should not become prideful at the height of his prosperity.

And you shall know in your hearts (that this was a 'training' experience).  Deut 8:5

Why Seven Days

All the agricultural holidays revolve around the number seven - the number of the Creator.  Seven days of Passover in the spring; seven weeks until Shavuot in the summer, and seven days of Succot in the fall. 

The seven days of Creation emphasize that creation was not by chance but rather the willful act of YHVH for a purpose.  Each time the number seven is found in Torah it is to remind us that YHVH is The Creator and Master over all things, including our prosperity. 

The Festival of Succot will continue into the Messianic age, and will be observed by all people, in honor of the One True God, YHVH Elohim.

"It will happen that everyone who is left of all the nations that came against Jerusalem will go up from year to year to worship the King, YHVH Sabaoth, and to keep the Feast of Tents (Succot), it will be that whoever of all the families of the earth doesn't go up to Jerusalem, on them there will be no rain. This will be the plague with which YHVH will strike the nations that don't go up to keep the Feast of Tents. This will be the punishment of Egypt, and the punishment of all the nations that don't go up to keep the Feast of Tents."  Zechariah 14:16-19