Part 2: Through coupling, the respective parts of MaH and BaN are channeled... It is already clear from the principle of sequential development (השתלשלות, hishtalshelut) that lights emerge from other lights. The channeling of the emergent light depends upon coupling through the arousal of the Yesods (of the parent Partzufim), for the Yesod possesses a unique power in this respect: this will be explained further in its appropriate place, with the help of Heaven.
...until everything is placed in the Female. There in a single whole is found everything that needs to exist in the light in question so that there will be no need to add or subtract. This is clearly the case, because the cause of the resultant light’s existence is only the coupling. Nothing can exist in any given subject without a cause. With the completion of the process of coupling, the first cause (the Male) has already completed giving what it has to give to the resultant light, and no other further causal factor acts in it. If so, nothing can exist in it that was not there already. It is quite clear that no other causal agent acts in the offspring that comes forth as a result of the coupling, for this offspring is precisely that which is able to emerge and exist only through the coupling. (There are no other concomitant factors.) Indeed, this is why this pathway was instituted as the particular pathway followed throughout the developmental chain of the lights. If so, once the coupling is completed, the cause (the Female) certainly contains all that has to exist in the resultant offspring that is to be built therefrom.