pages 53a-59b in sefer habria are a very special display of MOHaRa”N’s receptacology/manaology, and they include a discouse that we may call “the discourse of motarot”. the motarot are the seminal leftovers from the act of zivug in the world of self-concept (atzilut), and weren’t yet “frozen” and thus realized (shleimin) within the “pond” (brecha) of the feminine unproviding conceptual womb. according to rabbi natan, the seminal remains of the atzilutic “waters” (mayim) were expelled to the lower worlds, in which their consummated construction is conducted, and thus the immanent godhead is proved incapable of fully conceiving its whole vital plenitude, and turns out to be in need of the earthly manaic act which will complete and consummate the “enforming” (tziur) of divine life. and thus the matter is worded:

and this will be a great rule of thumb for you: that all that there is from ma’aseh bereshit in the high worlds whose construct has not reached its consummation by the light cannot be completed there [in the high worlds], and has to be repulsed downwards so that it may be completed by the lower ones [...] for the high [olamot] may not be fulfilled unless the lower ones act.

according to R’ Natan, the “empty/dry vessels” (manin yeveshin) are the earthly receptacles through which the tziur of the motarot is brought to fulfillment. in daf 54 he describes beautifully how the human neshama (nishmeta d’var nash) is that very realizateur which, by the “occupation with torah and with mitzvot” (esek hatora v’hamitzvot), completes the tziur of divine life and fulfills its aspect as the binah, hence – as the enformer, finalizer and realizer of the olamic pleroma.

(the incessant providence of nevi’u d’chayey bestowed to be ever-realized and always-consummated in the mana of malchut)

rabbi natan describes the malchut (the absolute mana, the final neshama) as a “grail of blessing” through which the higher vessels pour (“to pour/to add” – lehosif) divine creative energy into the world, as God first pours his vitality into the neshamot of israel, which are – being the most exterior/physical – the most important vessel, and then moves on to malchut and tiferet in a series of total internalizations.
in page 55b there is a description of the source of impurity, formlessness and destruction in the world: motarot which weren’t channeled downwards, and in that sense were nichratim (“cut off”), becoming contaminations (sigim) on the high worlds and blocking the movement of abundance from them to the earth. according to R’ Natan, this is the role of teshuva (which is the binah, which is shem ShaBTa”Y and israel’s occupation with the torah): to reform the sigim and to bring life back forth, and thus to redo the act of primal generation, renewing and reaffirming divine self-existence. this conclusion is derived from the connection between S”G (as in shem S”G [63]) and sig (“waste/contamination”), and as we know that teshuva is binah, we learn that the role of binatic repentance is to reform and fulfill the supernal waste which blocks divine action and providential direction.
what we learn from those dapim is that divine life has to be manifested, personalized, received and brought forth, in order to be fully formed. the reforming of divine seminal waste is the ta’am of teshuva, which is repentance through devotion to shem ShaBTa”Y, as well as occupation with mitzvot and with the fulfillment of divine law.