The Children of Israel began building the "Mishkan" (also called the "Tabernacle"--a portable sanctuary to house the Divine presence in their midst as they journeyed through the desert) on the 11th of Tishrei of the year 2449 from creation (1312 BCE) -- six months after their Exodus from Egypt, four months after the revelation at Sinai, and 80 days after their worship of the Golden Calf. The construction of the Mishkan, which followed a detailed set of instructions issued to Moses on Mount Sinai, lasted 74 days, and was completed on the 25th of Kislev; but the Divine command to erect the edifice came only three months later, on the 23rd of Adar, when Moses was instructed to begin a 7-day "training period."
During the week of Adar 23-29, the Mishkan was erected each morning and dismantled each evening; Moses served as the High Priest and initiated Aaron and his four sons into the priesthood. Then, on the "eighth day" -- the 1st of Nissan -- the Mishkan was "permanently" assembled (that is, put up to stand until the Divine command would come to journey on), Aaron and his sons assumed the priesthood, and the divine presence came to dwell in the Mishkan.
Links:
Parshah Terumah (detailed description of Mishkan with commentary)
Why It's Frustrating Having a Brain
More on the Mishkan
Chassidic Rabbi Yitzchak Meir Altar (1799-1866), author of Chiddushei Harim (a commentary on the Talmud and Shulchan Aruch), was a disciple of the Maggid of Koshnitz and Rabbi Simcha Bunim of Peshischa, and the founder of the "Ger" (Gerer) Chassidic dynasty. All his 13 sons had died in his lifetime, and he was succeeded (in 1870) by his young grandson, Rabbi Yehudah Leib Alter (the "Sefat Emmet").
On 18 Adar (March 1) a terrorist opened machine-gun fire on a van filled with Chabad yeshiva students as it began to cross the Brooklyn Bridge from Manhattan, critically wounding two young men and injuring two others. The killer had wished to fire at the Lubavitcher Rebbe—Rabbi Menachem M. Schneerson, of righteous memory—but could not get close enough.
While three wounded students—including one who had a bullet lodged in his brain —recovered, 16-year-old Ari Halberstam succumbed to his wounds five days later on 23 Adar.
Rabbi Alexandri said, “Master of the Universe! It’s obvious to You that we want to do what You want done. So what is holding us back? The yeast in the dough!” (Talmud, Berachot 17a)
What is so terrible about chametz, that once a year, for the Festival of Freedom, we must search, burn and destroy any trace of it in our possession?
Because yeast makes a little dough into a big loaf of hot air. And that pretty much describes the fundamental gameplay of all that imprisons you.
It's like the yeast that takes your healthy need to earn an honest living and blows it up into a desperate need for recognition and yet more recognition.
Or like the yeast that mixes in when you are about to do a beautiful mitzvah out of the sincerity of your heart, saying, “Yes! Do it! People will say you are such a tzadik!”
Or the yeast that appears when you are studying the wisdom of Torah and it whispers, “Soon you will be wiser than anyone else!”
It’s that yeast that ties every thought, every word, every deed you do to your ego, as though your existence is somehow invalidated if you do not occupy more and more space every day—with nothing but hot air.
You are its prisoner. It is your taskmaster. It has stolen your life from you, rendering you just another subject of an oppressive world you must satisfy and please.
On Passover, you are empowered to break your chains of bondage. To do a mitzvah only because it connects you to your G-d. To learn Torah wisdom only to become one with divine wisdom. To be yourself. To escape bondage to anything in this world. To be free.
And you begin by ritually eradicating a physical manifestation of that ego from our world. By selling and burning our chametz, we are empowered to set ourselves free.