בראשית, “In the beginning” is Chalah חלה, The Zohar ask how do we know that Chalah is the beginning and bring the verse from Numbers 15:20, “ראשית עריסתכם חלה”, “The first of your dough, chalah….”
Chalah reflects the light of the upper three Sefirot.
Because of the higher light in it, there is a need to remove a small part that represent the Yod י of Chokmah and reveals the light in the H ה of Malchut.
The letter ה in חלה is for Binah. We eat Chalah on Shabbat, which is the seventh day, where the Light of Binah is revealed.
The Zohar asks what is Chalah and answers: it is the seven species (Wheat, barley, grape, fig, pomegranate, olive and honey, which is made out of dates דבש תמרים). The 7 species represent the 7 Sefirot of the world of tikkun.
Chalah is the Shechina, that includes from the 7 species. Adam sinned with the connection to the Shechinah.
Wheat is the ‘Tree’ that Adam ate from and because he didn’t separate Challah from it.
Adam was the first human and after the sin he lost his spiritual and physical height and was considered the ‘Chalah’ of the world. When he was in the Garden of Eden he ‘dwelled’ in the higher levels but after the sin he was sent out to the world below with the Seven Sefirot from Chessed to Malchut.