The Talmud (Rosh Hashanah 10b-11a) cites two opinions as to the date of G-d's creation of the universe: according to Rabbi Eliezer: "The world was created in Tishrei" (i.e., the sixth day of creation--the day on which Adam and Eve were created--was the 1st of Tishrei, celebrated each year as Rosh Hashanah); according to Rabbi Joshua, "The world was created in Nissan." As interpreted by the Kabbalists and the Chassidic masters, the deeper meaning of these two views is that the physical world was created in Tishrei, while the "thought" or idea of creation was created in the month of Nissan. (see "Links" below)
Link: Our Other Head
According to the Talmud, the three Patriarchs of the Jewish people-- Abraham (1813-1638 BCE), Isaac (1713-1533 BCE) and Jacob (1653-1506 BCE)--all were born and passed away in the month of Nissan.
On the first of Nissan of the year 2448 from creation (1313 BCE--two weeks before the Exodus), G-d showed Moses the crescent new moon and told him, "When you see the moon like this, sanctify [the new month]." This ushered in the first Jewish month, and commenced the lunar calendar Jews have been following ever since.
On the eighth day following a 7-day training and initiation period, the portable Mishkan ("Tabernacle" or "Sanctuary") built by the Children of Israel in the Sinai desert was erected, Aaron and his sons began serving as priests, and the Divine Presence came to dwell in the Mishkan; special offerings were brought, including a series of gifts by Nachshon ben Aminadav, the Prince of the Tribe of Judah (similar offerings were brought over the next 11 days by the other tribes of Israel).
Link: The Mishkan
On the day the Mishkan was inaugurated (see above), "Nadav and Avihu, the sons of Aaron, took each of them his censer, and put fire in it, and put incense on it, and offered strange fire before G-d, which He commanded them not. A fire went out from G-d, and consumed them, and they died before G-d" (Leviticus 10:1-2).
Link: The death of Nadav and Avihu: The biblical account, with commentary; the mystical insights
Today is Rosh Chodesh ("Head of the Month") for the month of Nissan.
Special portions are added to the daily prayers: Hallel (Psalms 113-118) is recited -- in its "partial" form -- following the Shacharit morning prayer, and the Yaaleh V'yavo prayer is added to the Amidah and to Grace After Meals; the additional Musaf prayer is said (when Rosh Chodesh is Shabbat, special additions are made to the Shabbat Musaf). Tachnun (confession of sins) and similar prayers are omitted.
Many have the custom to mark Rosh Chodesh with a festive meal and reduced work activity. The latter custom is prevalent amongst women, who have a special affinity with Rosh Chodesh -- the month being the feminine aspect of the Jewish Calendar.
Links: The 29th Day; The Lunar Files
A special mitzvah, which can be fulfilled only once a year, is to recite the berachah ("blessing" or prayer) made upon seeing a fruit tree in bloom: Blessed are you G-d our G-d, king of the universe, who left nothing lacking in His world, and created within it good creatures and good trees with which He gives pleasure to people. Today is the first opportunity to make this blessing, but it can be done anytime during the month of Nissan (referred to by the Torah as "the month of spring" ). Many visit botanical gardens during this time, so as to avail themselves of an opportunity to observe this beautiful mitzvah.
Link: Trees
Beginning today, and continuing through Nissan 13, we recite the verses (from Numbers ch. 7) describing the offerings made by the "princes" (nesi'im) of the 12 tribes of Israel (see "Mishkan inaugurated"). Today we read of the gift bought by Nachshon ben Aminadav, the nasi of the tribe of Judah, on this date. Tomorrow we read of Issachar's gift, and so on for the 12 tribes. On the 13th of Nissan we read G-d's instructions to Aaron regarding the kindling of the menorah, which represents the participation of the priestly tribe of Levi.
Following the verses of the day's "Nasi," we recite a short prayer in which we say, "...if I, Your servant, am from the tribe of ___ whose section of the Nasi I have read today in Your Torah, may all the holy sparks and holy illuminations that are included within the holiness of this tribe shine upon me, to grant me understanding and intelligence in Your Torah and my awe of You, to do Your will all the days of my life...."
Text of today's Nasi in Hebrew and English.
Links: Tribes.
Look deeply and you will see that the Torah does not know of man and woman as separate beings.
Each act is performed once through a single body—a body that in our world may appear as two, but which the Torah sees as one.
On the contrary, for both to be assigned the same mitzvah would be redundant, for why should one half of the body do that which the other has already accomplished?
Just as a man fulfills the mitzvah to be fruitful and multiply through the agency of his female counterpart, so does a woman wrap tefillin or wear tzitzit on the body of her male counterpart.
For just as man and woman were first created as a single form, so too, before each soul descends below, they begin as one.
It may be at times that only half a soul must descend for its divine mission, while the other half waits patiently above. And when it will return, they will merge once again.