Simchas Torah
Nagilah V'Nismecha Bo:
The Yalkut Shimoni (Parshas Pinchos, Remez 682) says a moshol of a king who makes a seven-day feast. Throughout that entire time, his sons took care of the guests. Once the seven days ended, he told his sons, "I know that you were busy with the guests for the past seven days. Now we can rejoice together. Sit down and enjoy yourselves."
So too, for the seven days of Sukkos, Klal Yisroel is busy taking care of the korbanos sent by the nations of the world, as Rav Pinchos says that the 70 cows offered during yomtov represent the 70 nations of the world and are brought as korbanos so that they will have no power to destroy the Jewish people. Once these seven days end, Hashem tells His people that they should now sit down and celebrate with Him.
Taking Out All the Torahs:
Sefer Yesod Yosef (Perek 79) explains the minhag on Simchas Torah of taking out all the sifrei Torah from the aron by saying that this shows Hashem's great love. When a father truly loves his son, he opens the doors to everything he owns and allows him to take whatever he wants. So too, we empty the Aron Hakodesh as a sign that Hashem has opened all His treasure houses of holiness for us, and He enables us to take as much as we want.
The Simcha of Completing the Torah:
The Dubno Magis zt"l asks why we celebrate Simchas Hatorah on the day we finish Parshas V'Zos Habracha, rather than on the sixth day of Sivan, when we received the Torah. He answers with the following moshol:
There was a king who had an only daughter. When she reached marriageable age, she told her father that she wanted to marry a boy from a simple family, who has good character traits and isn't haughty. The king wasn't happy about this, but he wanted to give his daughter what she wanted, so he sent his servants to find such a boy. They came to a remote village and found a smart, refined young man. After conversing with him, they concluded that he would be a good groom for the king's daughter. They told him that the king desired to meet him, and he agreed to go with them.
When the king met the boy, he was very impressed with his character. He asked him if he would marry his daughter, and the man said that he would.
A year after the wedding, the husband told the king, "I want to invite you to my wedding with your daughter."
The king didn't know what he meant. They had already been married for a year!
The son-in-law explained, "At the wedding, while everyone else rejoiced, I was sad and anxious. I wondered why the king would want his daughter to marry a simple villager like me. I thought that there must be something seriously wrong with the bride, or else he never would have agreed to this match. Now that a full year has gone by, I know that my wife has no flaws. Therefore, I can now finally be happy, so I want to make another marriage celebration."
Of course, the king was very happy to hear this, and he participated in the second wedding ceremony with joy.
When Klal Yisroel accepted the Torah, their joy was not complete. They wondered why He was giving His precious gift to them. Therefore, they assumed it must contain rules that they couldn't possibly keep. After learning the entire Torah, however, they saw that it was perfect and contained only pleasantness. That is why the completion of the Torah is the time for true joy and celebration.
The Days of Joy Start Now:
The Ropshitzer Rebbe zy"a (quoted in Sefer Chemdah Genuzah, Chelek Bais) explained the yomtov of Simchas Torah with a story of a villager who was looking for a wife who would agree to live in his small town. However, when he did get married, his wife persuaded him to move to the big city. When he arrived there, he asked the shamash to inform him about all the local customs, promising to pay him for this service.
On Rosh Chodesh Elul, he was leaving shul after Shacharis, when the shamash stopped him and informed him that the custom was to recite Tehillim after davening on that day. When he got home, he told his wife, “I told you that living in a big city would only cause me trouble. Today, they made me stay late after davening to say Tehillim.”
His wife comforted him, and he calmed down.
A week before Rosh Hashanah, the shamash knocked on his door early in the morning and told him that he had to get up to say Selichos. He was upset that he had been awakened so early, and, once again, his wife comforted him.
On erev Rosh Hashanah, the shamash knocked on his door at 3 am to wake him up for early Selichos. On Rosh Hashanah, the shamash took him to shul and kept him there until 2:30 pm. He did the same thing on the second day of Rosh Hashanah. Right after his seudah ended, the shamash told him it was time for Minchah. The next day, he told him that it was Tzom Gedaliah, and he couldn't eat at all. Every day of the Aseres Yemei Teshuva, he woke him up early for Selichos.
On erev Yom Kippur, the shamash knocked on his door and announced, "The shochet is coming!"
The man got scared and told his wife, "Now they are going to slaughter me!"
His wife comforted him and explained that the shochet was coming for kaparos, not for him.
In the afternoon, the shamash told him to come to shul for Minchah. After Minchah, the shamash told him to sit down on the ground, and he gave him 39 lashes. He went home and told his wife that he had been lashed. While he was talking, the shamash arrived to take him back to shul.
The next day, the shamash brought him early to shul and told him that he was going to pray all day, without eating or drinking anything. After Yom Kippur, things went normally for a few days. He was happy that it looked like life would be easier from now on.
On the first day of Sukkos, when the shamash showed up to take him to shul, he told his wife, "He's coming to bother me again. Let's hurry back to the village."
She managed to calm him down again. When he got to shul, he was handed a stick (lulav) and a lemon (esrog), and told to shake them. Davening took a few hours, and he was very angry when he got home.
On erev Hoshanah Rabbah, the shamash brought him to shul and told him to stay up all night saying the tikkun and Tehillim. On Shemini Atzeres, he was very angry at his wife and at the entire city for making him so much trouble.
On the night of Simchas Torah, he was invited to a large seudah, where he was given a lot to eat and drink. On the morning of Simchas Torah, the kehillah davened quickly, and a large Kiddush was set up. He ate and drank and felt happy. He then went home and told his wife, "The good days have finally begun."
The Rebbe concluded, "This is the inyan of Simchas Torah."
Drinking Wine:
Sefer Shivchei Baal Shem Tov relates that one year on Simchas Torah, the inner circle of the Besht zy"a was dancing and drinking a lot of wine. The Besht's wife told her husband that they wouldn't have any wine left for Kiddush or Havdalah. She asked him to tell them to stop drinking.
He told her, “Ok. You should go tell them to stop drinking and to go home."
When she saw them dancing in a circle, she saw that a fire was burning around them like a chuppah. She then went personally to bring them more wine.
The Besht then asked her, "Did you tell them to leave?"
She replied, "You should have told them yourself!"