from ifdawn.com:

Da’at

Da’at is a “conjectured” sephirah that falls on the path of Gimel. In Hebrew, Da’at is “knowledge, perception, or learning.” It is not really a sephirah; it is a “result” of it’s location on the Tree of Life. It is midway on the longest path, and central in the upper hexagonal array. Binah and Chochma straddle the polarity between undefined knowledge and differentiation; Keter and Da’at straddle the polarity between cosmic consciousness and individual consciousness.

Da’at really is knowledge in the “Biblical Sense-” it is the focal point of the mystical union that is prescribed for sanctified couples to perform on Shabbat night, consummated at the darkest hour.

This joining opens a path for the Shekhina – a Hebrew word for the immanent aspect of the Creator, seen in Jewish philosophy as the female aspect of God. The “above” aspect of Shekhina is Binah, and the “below” aspect is Malchut.

The Shekhina, crowned as the Shabbes Queen, is welcomed with the reading of the Song of Songs, Solomon’s love poem of yearning for closeness to the Creator Before Time, Lecha Dodi to welcome the bride, and the aramaic K’Gavna prayer from the Zohar, read in the Kabbalat Shabbat service, at sunset:

 

K’Gavna

Just as the Sephirot unite above in Oneness without evil so Sephera Malchut unites below in the secret of Oneness so She may join those above One receiving One. The Holy One, Blessed is He, the One above, does not sit on His Throne of Glory until She below, the Shabbes Queen, is made over in the secret of Oneness like His that they may join in a Oneness of Oneness. Thus have we set forth the secret of G-D’s Oneness: His name is One.

This is the secret of Shabbes: She (Malchut) is called Shabbes when One, when She is united up in the secret of One, occurring in the fullness of Shabbes, for then the Holy Throne of Glory unifies with the secret of Oneness, and becomes ready for the Holy King to mount it, when Shabbes arrives, She unifies Herself and divests Herself of the other side, all harsh judgements are removed from Her and She unifies with the Holy Light, with Holiness, and crowns Herself with many crowns in behalf of the Holy King. All dominions tremble in agitation and bearers of trials flee from Her together and Her appointment overwhelms, Her dominion arises, and then, with completion, Her myriad creations rejoice. Her face glows with Heavenly Light, and She takes those below who see Her up as Her Crown, and they crown themselves with Shabbes Souls.