1. Back to back (Achor be-Achor): no Light of Hochma and no need (from downward or upward) for Hochma and Bina to be connected.
2. Face to back (Panim be-Achor): there is Hochma in Aba, but Ima has no need to receive it;
3. Back to face (Achor be-Panim): Ima needs the Light of Hochma while Aba doesn’t have it.
4. Face to face: (Panim be-Panim): Aba desires to bestow, and Ima desires to receive the Light of Hochma in order to pass it to the lower ones.
The state “Face” means handing over the Light of Hochma; “Back” means connection solely in Hassadim or the lack of connection.
Face to back is a constant state in the world of Nekudim, when there is Hochma in Aba but Ima is unwilling to receive it. This state can be permanent since it doesn’t result in breaking. This state can continue in the world of Atzilut, like during the preparation stage, in the state of anticipation (standby mode).
The system is ready, and as soon as a desire to be corrected is raised by the broken souls, Aba and Ima’s adhesion (Zivug) immediately occurs, thereby passing down the Light from Above. But MAN, a plea, the prayer of the lower ones, is mandatory. It serves as an agent opening the so-called faucet holding back the flow of the Light, and it starts streaming downward.
A state in which the system stands by is regarded as face to back. Aba turns its face to Ima, who turns its back. But as soon as MAN, the lower one’s desire, rises up, it affects Ima, which turns to Aba, followed by their adhesion (Zivug) in the state of face to face, and the Light of Hochma passes downward to the souls.
From the 2nd part of the Daily Kabbalah Lesson 12/20/10, “Study of the Ten Sefirot”