Every new state is born only under the condition that the former state completely exhausts itself, similar to how a grain planted in the soil needs to rot completely in order for a new stage of life to be born from its former state, which is then perceived as unneeded and useless. This is why it is written about the holiday of Purim that Zeir Anpin sleeps while Malchut becomes immersed in darkness due to this. Only from this state of darkness do we attain the greatest Light, the state called Purim, which corresponds to the End of Correction.
If Zeir Anpin does not bring Light to Malchut, we feel that we are in exile and cannot tune into Malchut and unite. However, suffering and darkenss force us to demand strength from Zeir Anpin to accomplish our unification, in order to tune into Malchut, the one common soul. This is how we give rise to our next degree.