On the holiday of Shavuot the Torah asks to bring different kind of sacrifices.
“וְהִקְרַבְתֶּם עוֹלָה לְרֵיחַ נִיחֹחַ, לַיהוָה”
“but ye shall present a burnt-offering for a sweet savour unto YHVH”
On Passover the sacrifices described as (Numbers 28:19)
“וְהִקְרַבְתֶּם אִשֶּׁה עֹלָה לַיהוָה”
“but ye shall present an offering made by fire”
The English translation can not reveal the secret but the Zohar explains that on Shavuot we receive the Torah after a cleansing process of seven weeks. The type of the sacrifice is on a higher level because on that day we achieve purification and Malchut can have unification with Zeir Anpin.
The bride comes to the groom after seven pure days in order to have pure unification and connect to the life aspect that is Binah.
We have six days to work on our vessels and prepare it for unification with the light of Shabbat. When we prepare it properly then we can elevate to Binah and connect to the Life of the Tree of Life. Without a good and pure vessel we stay at the lower level of Tree of Knowledge Good and Bad.
Daily Zohar # 1390 – Seven is for purity