The list in this week's Torah portion of sacrifices during the different times in the year is precise to the very last detail. We might well wonder why this is so.
Two sheep are sacrificed every day in the Temple, one in the early morning and one in the evening. This teaches us about the eternal link between the Children of Israel and the Holy One, Blessed be He. What took place in the morning is repeated in exact detail in the afternoon: "I am G-d, I have not changed, and you, the Children of Iccasrael, have not been destroyed." [Malachi 3:6].
On Shabbat two additional sheep are brought, to signify the "extra soul" which we are privileged to have on this holy day.
On Rosh Chodesh, the beginning of a new month, two bulls are brought, as a symbol of the power of fertility linked to the rejuvenated month. This is added to the strengths of the previous month – one ram for the power and seven sheep for the sanctity of the times of the year, which is symbolized by the number seven, and is renewed at the beginning of every month. In addition, one goat is brought as a Chatat Sacrifice for atonement, in order to mend the faulty reality of the changing world.
On Pesach the same sacrifices are brought as on Rosh Chodesh, because the month of Nissan is the first one of the entire year. The same sacrifices are brought on Shavuot in addition to others – seven sheep, two rams, and one bull, aside from a goat and special Shelamim Sacrifices, peace offereings, for Shavuot. This shows the bidirectional character of the service on that day, celebrating when the heavenly and the earthly were joined together in the giving of the Torah. Rosh Hashanah, Yom Kippur, and Shemini Atzeret differ from the other holidays – with sacrifices of one bull, one ram, seven sheep, and a goat – all to teach about the primal thought which was not preceded by any other, and is therefore represented by a single bull. On Succot, aside from the seventy bulls which atone for the sins of the rest of the world, the number of rams and sheep is doubled, to teach us that Succot brings with it a type of "additional soul," twice what is given on the other holidays.
The list of holidays and their sacrifices is precise, and it corresponds to the ten "shells" of mysticism. The simple Tamid Sacrifice is a symbol of the constant abundance provided by G-d, corresponding to the shell of keter, the crown. The additional Mussaf sacrifice of Shabbat, the day which reminds us of the day of Creation, corresponds to chochmna, wisdom, which served as the basis for the way G-d created the world. The Mussaf of Rosh Chodesh, the additional sacrifice, which is a symbol of constant renewal, represents binah, understanding, the root of time renewal, which gives Israel the power to sanctify time during the year. This is related to the line in the liturgical poem, Bar Yochai, about the "green line renewing the new months."
The other holidays which were instituted as a result of the Exodus from Egypt, correspond to the seven shells of "binyan" – building up reality. The first day of Pesach is chessed (charity) when we were taken out of Egypt without any merits to our credit. The seventh day of Pesach is gevurah (heroic strength) when Egypt was punished. Shavuot is tiferet (glory) which stands for the giving of the Torah. Rosh Hashanah is netzach (eternity) when the eternal kingdom of G-d is revealed. Yom Kippur is hod (beauty) for the service by the High Priest. Succot stands for yesod (foundation), when the covenant is renewed in the joyous festivities of Beit Hasho'eivah, and Simchat Torah corresponds to malchut (royalty), when the King is blessed.