Thus in the order in which things developed, they are garments in one aspect, but afterwards, during their period of rule, they are considered in a different category and then they are “worlds”. However, here it is the very aspect that was previously in the category of garments that remains as worlds, since they lack the aspect of being garments inasmuch as they lack the body that is being clothed, as stated above. And this is only because they now need to be built in order to be able afterwards to serve as garments to Atzilut in this way, and then they will serve in their proper function.
Life of Atzilut
Kalach Pitchei Chokhmah 46:13