1. Sukkot is a celebration of the harvest. We may learn this directly from the Torah (Devarim 16:13): the time to observe Sukkot is set "at the end of the year when you gather in the results of your work in the field." So critical is the agricultural dimension to Sukkot's significance, one of the holiday's names is derived from this aspect: "Chag ha-Asif" (Festival of the Ingathering).
This meaning of Sukkot aligns the festival with a paragraph in the Shemoneh Esrei (a.k.a., Amidah); agricultural success is a theme common to both the holiday and Birkat ha-Shanim (The Blessing of Years). The berakhah reads thus: 'Bless on our behalf (aleinu), Hashem our G-d, this year (shanah) and all the kinds of crops for the best; and give blessing on the face of the earth (adamah), and satisfy us with Your bounty; and bless our year like the best years. Blessed are You Hashem who blesses the years.' The celebration of Sukkot ought to raise our kavvanah in praying Birkat ha-Shanim. (Sukkot is just one example of the alignment between a holiday and a berakhah of the Shemoneh Esrei. The presence Rosh ha-Shanah and Yom Kippur heightens awareness of the paragraphs about teshuva (repentance) and selichah (forgiveness); the presence of Pesach elevates our intention in the berakhah for ge'ulah (redemption); etc.)
2. Birkat ha-Shanim is not merely a petition for agricultural wealth. If it were only this, perhaps its name would be Birkhat Parnasah (Blessing of Sustenance). But the word "parnasah" (sustenance), a word we might expect to find in a request for a sustaining harvest, does not even appear in this blessing.
At this time of year, we say that The King is in the fields. We understand that now HaShem has come out onto our turf, but what The King does in the fields is not clear. Also at this time of year, we call HaShem "Av Ha-Rachamim" ('The Father of Mercy', or more literally 'The Father of Wombs'). The temporal juxtaposition and spiritual alignment of these two images, allows the explication of The King coming into the fields in terms of The King being Av Ha-Rachamim. We may learn that The King is in the fields --as father-- inseminating and --as wombs-- nurturing. HaShem is in the fields, laboring as a farmer, seeding and caring for the plantings; and we, as the recipients of Our Father's great rachamim (mercy), we are the crops.
When I pray Birkhat ha-Shanim, I pray that I transform from mere soil and rain and seed, that I unify and rise up from my simply being matter; I pray that the elements prepared carefully over the preceding years -- the nutrients and moisture deposited gradually into my soil -- the experience and love I've received into my personal history -- may be turned from raw potentialities into flourishing actuality of being.
3. Sukkot is a celebration of freedom. We may learn this directly from the Torah (Vayikra 23:42-43): 'You shall live in booths seven days... in order that the future generations may know that I made the Israelite people to live in booths (sukkot) when I brought them out of the land of Mitzrayim....' ("Mitzrayim" literally means 'narrownesses' and it refers to Egypt.) In the Zohar (Emor 103a), the sukkah is understood as symbolizing the shadow of faith in which Jews live, and then it is taught 'whoever abides under the shadow of faith acquires freedom for himself and his descendants in perpetuity....'
Since Sukkot aligns with Birkhat ha-Shanim, this meaning of Sukkot suggests that hidden within the berakhah is the theme of liberation. To find this dimension, some additional resonances of the berakhah's words must be brought out. Let us read "aleinu", not 'on our behalf', rather more simply as 'upon us'; "shanah", according to its verb "shoneh", as 'change'; and "adamah" as 'adam', 'human'. Thus the berakhah reads: 'Bless upon us (aleinu), Hashem our God, this changing (shanah) and all the kinds of crops for the best' -- that is, bless us to change into the best crop for You, '... and give blessing on the face of Humanity (adamah)' -- and this is a blessing not only for You but also for we humans, '... and satisfy us with Your bounty' -- change us through Your rachamim which is bountiful in this time of year, not through harsh judgement, '... and bless our changing like the best changings' -- bless us to change as well as our exalted fathers and mothers, 'Blessed are You Hashem who blesses the changings' -- we rely on you utterly for all changing to the best is brought about by You. This changing is connected with liberation. When we went free out of Egypt, we dwelled in HaShem's presence, in HaShem's shelter, in HaShem's sukkah; and in our freedom, we were blessed with our change, our transformation, our consecration from a collection of unrefined slave-matter -- dirt and sweat -- into Community of Torah. Birkhat ha-Shanim is a supplication prayer to be freed from the low ground and brought out into bountiful harvest of HaShem; this berakhah is a prayer that I personally might be freed from the mud, and that the Jewish people altogether, from our many wombs, be freed from our state of dispersed potentialities and brought into fruition.
4. Why do we need both Pesach and Sukkot if both celebrate liberation? In Torat Ha-Moadim (p.113), Rav Goren teaches that there are three kinds of slavery and three corresponding kinds of freedom. (1) There is physical enslavement in performing labor not directed toward HaShem. We are under this enslavement when we work for Mitzrayim. And there is physical freedom. We are blessed with this freedom when HaShem brings us out of Mitzrayim. (2) There is spiritual-cultural enslavement into the values and norms of foreign powers. We are under this when we think it better to live in Mitzrayim than to raise up into HaShem's promised land. And there is spiritual-cultural freedom. We are blessed with this when we receive the Torah. (3) There is enslavement to our lusts. We are under this when we raise up golden calves, seeking unity with mundane things and thus worshipping idols instead of HaShem. And there is freedom from these lusts. We are blessed with this when we elevate and sanctify our wealth, when we find in Creation the presence of the Creator, when we form in the light of HaShem the void matter of Ha-Olam Ha-Ze.
The Torah gives us archetypes for these enslavements and freedoms in the stories of Mitzrayim. This wisdom opens the possibility that we understand how each kind of enslavement and freedom is present in our living today. In order to actualize this wisdom, in order to realize our state, the Torah commands to observe holidays corresponding to each kind of enslavement and freedom. The most basic kind, physical enslavement and freedom, begins our holiday cycle; this kind is our focus on Pesach. A more subtle kind, spiritual-cultural enslavement and freedom, is brought out in the next hag; this kind is our focus on Shavout. The most hidden kind, enslavement and freedom of lusts, finishes the cycle of pilgrimage festivals; this kind is our focus on Sukkot.
Because Sukkot is a celebration of freedom from lusts, Sukkot rises up in the Shemoneh Esrei as a berakhah about material plentitude. In Birkat ha-Shanim, we are reminded to elevate the harvest and not become dragged down and enslaved in our insatiable lusts. On Sukkot we are commanded (Vayikra 23:37) 'to bring near (l'hkriv) fire-offerings to HaShem', that is, we should raise up to HaShem our wealth; and (Birkat ha-Shanim) '[from] the face of the earth' -- from our low-ness -- You will 'fill us up with Your best' -- You will elevate us with your highest.
5. In the last line of Birkat ha-Shanim, two actions of blessing are mentioned: 'Blessed are You HaShem' -- here we bless HaShem, 'who blesses the years/changes' -- here we recall HaShem rendering blessing onto us. One blessing reflects the other. The action in Shamayim (Heavens) -- the giving of bounty -- inspires our love and blessing; and furthermore, as the Chassidic masters teach, our action upon the earth of blessing inspires the outpouring of bounty from Shamayim. How do we learn that on Sukkot our blessing brings forth HaShem's Chesed (overflowing loving-kindness)? In the Mishna, Sukkot is understood as the Day of Judgement for the Water of the coming year, and from Kabbalah, we learn that water represents Chesed; so Sukkot is a Day of Judgement for Chesed and the blessing of the raining down of Chesed is rendered according to the merit of our water libations and our blessing for the best of years. We may also learn that being a good harvest encourages the goodness of HaShem from a teaching of Rebbe Nachman: the eater gains energy from the food and that the food receives energy from the eater. May our actions in this year be a feast for our Creator, and in our rising up in service to our Creator, may our latent sweetness be brought forth into fruition.
Hag Same'ach!
(I am indebted to "Popular Judaica Library" whose volume on Sukkot pulls together much of the source material used here.)