My posts yesterday, FOT 2008, Day 5 and An Addendum on God Working Things Out, had some Feast of Tabernacles themes: this life is a temporary dwelling, and we rely on God in the midst of it all.
The temporary dwelling part is more Armstrongite than Jewish, and it's based on biblical passages that treat the human body as a tabernacle for the soul, or (for Armstrongites) spirit (John 1:14; II Corinthians 5:1-4). Leviticus 23:42-43 views the Feast as a commemoration of Israel's sojourn in the wilderness, right after the Exodus: "You shall live in booths for seven days; all that are citizens in Israel shall live in booths, so that your generations may know that I made the people of Israel live in booths when I brought them out of the land of Egypt: I am the LORD your God" (NRSV).
Israel was supposed to be in the wilderness for a temporary amount of time, before she entered the Promised Land. Through that duration, she was completely dependant on God, who fed and protected his chosen people. Jews today do not put a roof over their sukkot, but they leave themselves vulnerable to the rain, reminding themselves of their absolute dependence on God. For Christians, the land of Canaan symbolizes the rest that all believers will one day receive, presumably in the afterlife. This implies that this life is our wilderness experience. We are in a temporary dwelling, and it is rough, the same way that the wilderness was hard for the Israelites. But we trust in God and hope for something better.
I remember a Touched by an Angel episode in which Montel Williams plays a cult leader, Brother David. Cynthia Nixon of Sex and the City fame plays a lonely young woman named Melina, who gets sucked into the cult. Before she hooks up with Brother David, Melina's life seems to be going nowhere. She wants to have kids, but her ex-boyfriend doesn't. She looks for a job that involves working with children, but she gets stuck with telemarketing instead. As she pursues a better life, she gets sucked into Brother David's cult, and he takes a special interest in her.
At the end, Brother David asks everyone to drink poison grape juice so they can be together in heaven, where (in his delusional mind) he will sit at God's right hand, as Melina sits at his. Melina thinks that everything finally makes sense: no wonder she never fit in on earth! She wasn't meant to be here. She's supposed to be in her heavenly home, with Brother David. But Monica (the angel) persuades her that she's to stay on earth through the tough times, relying on God to see her through.
For some reason, we're on this planet. Of course we're supposed to be here! We're here, right? God wouldn't arrange things that way if they weren't part of his plan. And we're here to build character. Israel was in the wilderness so that she'd become humble, learn to obey God's commandments, and depend on God for her provision (Deuteronomy 8). In the Promised Land, she could easily forget God in her prosperity (vv 17-19), so God gave her the Feast of Tabernacles to remind her where she came from, as well as to celebrate her prosperity as a gift from him. And the festival can perform a similar function for Christians.