There are times when I am pondering these verses when I have to throw my hands up and and say, "what could they possibly be thinking of?" Then after a moment or two the insight arrives. See what this is below:
Verse 168. Why do you call it the eight? Because with it the eight are begun, and with it the eight numbers are completed. In function, however, it is the seventh one. And what are [the eight] that were begun? This is the fact that a child enters the Covenant of Circumcision when eight days old. Are they then eight? They are nothing more than seven. Why then did the Blessed Holy One say eight? Because there are eight directions in man. What are they? They are as follows: The right and left hands; The right and left legs; The head, the body, and the Covenant as an arbitrator; And his wife, who is his mate. It is thus written (Genesis 2:24), "And he shall cling to his wife, and they shall be one flesh." They are the eight, and they parallel the eight days of circumcision. Are they then eight? They are nothing more than seven, since the body and covenant are one. It is therefore eight.
Commentary: On second thought this passage is exceedingly rich. Everything that comes from one returns to one by the mediation of one. These words are paraphrased from an ancient mystical text called the 'Emerald Tablet of Hermes.' They illustrate the principle of unity that is demonstrated through the ten Sephiroth. Eight days after a Jewish male is born the circumcision takes place a sign of the Covenant between Israel and God. The circumcision can also be a symbol for the removal of the klippoth that surround us due to our imperfect thinking. It is also meaningful when it calls our attention to the Covenant as the arbitrator. This arbitrator is the go between that effects the covenant by making it possible for us to resist the Yetzer Hara. Without this covenant chaos would triumph and our lives would be subject to the whims of chaos. Instead what the covenant does for us via the mystical circumcision or separation of the physical element of connection to the Yetzer Hara is to allow us to cleave to God. This is described as clinging to your wife and then becoming one flesh. The allusion here about the eight that is really seven refers to the renewal of eight which is the starting over point from the seven days of creation representing the divine plan. In any moment choose this moment for example it is important to recognize our own personal connection to this covenant by realizing where we stand in mind. What are we thinking about and how can we unify our thoughts then with the Torah which in effect becomes the software for the keeping the Covenant. Think about it. Whenever the Covenant was given it was given by Hashem to man. This is a gift of realization. When you unify your thoughts with Hashem you follow the ways of creation within the sphere of your own experience. Try bringing into your conscious experience the idea of the Covenant and then through prayer, mitzvah and Torah study you will set up the conditions for the fertile blossoming of what is called becoming one flesh above.
It is this starting over point that is crucial to understand this verse and indeed the fundamental basis of Kabbalah and the ongoing creation through our thoughts and mitzvahs throughout our study of Torah. We are always trying to relate our insights through the central nexus of Torah. Nexus is a great description here because it allows us to understand the functionality of Torah as a kind of stargate through which our lives and world(s) experiences pass through. By now you may have begun to realize that we have jumped up to another level of understanding of the Bahir. This level ascertains directly the locus and outward radiation of thought as it permeates the universal field of ideation. The numbers that are used are confusing because we have been for the most part working in a linear fashion. From here on in the we will be considering these Sephiroth multidimensionally. In verse 168 and the next few verses we look at the flow of energy from above to below and from below to above. The insight here is to recognize that thought itself is the carrier wave of this energy as thought bonds with like thought producing the offshoots of thoughts ending up in the creation of worlds upon worlds without end.
Example: A King has two ministers who want to build a garden. They speak about the plants and the plants and then one of then has an idea to build a waterfall. Then the other one thinks of a waterwheel and subsequently they figure out how to bring the water inside the palace so that the queen will be able to have running water at her disposal night and day. Two weeks later the project is finished. Yes there a beautiful garden but in addition that morning the queen arose and took her bath only a few short steps from her bed chamber placing her in such a good mood that she advised the King to promote both ministers for their ingenuity.
Thought never stops its cycle of creation-manifestation. What started out as a an idea for a garden turned out to be much more than this. Kabbalah then is the explanation of the cycle of extension that evolves from every thought. Knowing these extensions we may then direct our intention accordingly in line with Torah, in coorespondence with the creator blessed be he.