On the Shabbat before the Exodus--Nissan 10th on that year--the first-born of Egypt, who occupied the senior positions in the priesthood and government, fought a bloody battle with Pharaoh's troops, in an effort to secure the release of the Israelites and prevent the Plague of the Firstborn. This "great miracle" is commemorated each year on the Shabbat before Passover, which is therefore called Shabbat HaGadol, "The Great Shabbat." (This is one of the rare instances in which a commemorative date in the Jewish calendar is set by the day of the week rather than the day of the month.)
For more on the war of the Firstborn, see here.
Miriam, the sister of Moses, passed away at the age of 126 on the 10th of Nissan of the year 2487 from creation (1274 BCE) -- 39 years after the Exodus and exactly one year before the Children of Israel entered the Holy Land. It is in deference to her passing that the "Great Shabbat" is commemorated on the Shabbat before Passover rather than the calendar date of the miracle's occurence, Nissan 10.
Link: About Miriam.
Three days after the two spies dispatched by Joshua scouted the city of Jericho (see entry for "Nissan 7" above), the children of Israel were ready to enter the land promised by G-d to their ancestors as their eternal heritage. As they approached the Jordan with the Holy Ark carried by the Kohanim (priests) in their lead, the river parted for them, as the waters of the Red Sea had split when their fathers and mothers marched out of Egypt 40 years earlier. (Joshua 4)
In today's "Nasi" reading (see "Nasi of the Day" in Nissan 1), we read of the gift bought by the nasi of the tribe of Dan, Achiezer ben Amishadai, for the inauguration of the Mishkan.
The Shabbat before Passover is termed Shabbat HaGadol ("The Great Shabbat") in commemoration of the "great miracle" that happened in Egypt on this day, heralding the Exodus from Egypt five days later (see "Today in Jewish Hstory"). Shabbat HaGadol customs include reading a portion of the Haggadah (from "Avadim hayinu..." to "...al kol avonotainu"), which tells the story of the Exodus; it is also customary that the rabbi of the community delivers a lecture in which he elaborates on the laws of Passover and their significance, in preparation for the festival.
Know as clear as day and contemplate this deeply, that He who emanates all into being is He who rules and judges this world. In the heavens above and on the earth below, there is nothing else. (Deut. 4:39)
The same G‑d who transcends all time and space is the same G‑d manifest in all the forces and fields of physics.
The same G‑d from whom all existence emerges is the same G‑d who conceals that truth from every conscious being, providing space for each one to be that which it is.
The same G‑d from whom all life extends is the same G‑d who restrains that energy, with kindness, so that finite creatures can exist, to the tiniest worm hiding in the bowels of the earth.
And when you know all this, and you contemplate it well…
…that the very substance of each thing is nothing more than an articulation of divine energy, that even time and space extend from Him at will, as do the very limitations and sense of existence of each creation, that darkness is His presence as much as light, hiddenness as is revelation, matter as is energy, somethingness as is nothingness, for He is both beyond and within each place, moment and thing…
…then you will know that there really is nothing else. Nothing else but the one G‑d.
As the Baal Shem Tov would say in simple, succinct form: Divine energy is all there is, and everything is divine energy.