...in order to be completed thereby. I.e. in order to emerge sequentially with all its parts fully revealed.
This is because the lights of the one (the offspring) can be completed only through the lights of the other (the Female in which it is formed). This is the principle of sequential development that I have discussed.
When it has reached the stage where all its details are visible... Two things must be understood about each level (i.e. each Partzuf): the number of details it includes, and the degree of power they have. The full tally of all the constituent details must be revealed (at the time of birth) because each detail is the root of one function or of some condition governing one function. However the degree of power merely governs whether the function itself is carried out with greater or lesser power (e.g. with mature or immature mental powers). Accordingly the revelation (i.e. differentiation) of all the details has to come before the resultant light is (actually) revealed to the outside at birth, in order that it should be complete in all its powers. For afterwards there will be no additional revelation of any further component power. There can only be an increase in the force exerted by the existing component powers themselves. Indeed, there are different periods of time according to the order of gradation. There is a time for the details to be revealed, and when this time comes to an end, no further details can be revealed. Later there comes a period when the power of those particulars that have already been revealed is increased.