Ramchal now steps back from the end for a while and returns to the beginning — to the very start of creation. He’ll be using Kabbalistic terminology but we’ll do our best to bring it all down to earth.
“All the sephira-levels that G-d created” that is, all the non-material building blocks that went into the creation of the world known as the sephirot (plural of sephira), “were (originally) arranged in order, with one under the other”. In fact we learn that, “everything’s in place (ideally) when the more extraneous sephira-levels are below the more exalted ones and are subservient to them, which is how things will be in The World to Come.”
His point is that order and proper hierarchy are the ideal. It had been in place at the beginning and will be in place again in the end. “But everything was damaged” — everything suddenly changed for the worse — “when the ‘husk’ rebelled against its Master.
The “husk” is another name for the yetzer harah (which on both a personal level and a cosmic one is the resistance to G-dliness). It’s referred to as a “husk” or “shell” because it comes about before the “fruit” of G- dliness does, because it preserves the fruit (just as the yetzer harah preserves society, for without it there’d be no childbirth, civilization, etc.), and because like all husks and shells the yetzer harah is destined to be cast aside when it no longer serves its purpose (as we’ll see).
For “when the husk rebelled against G-d and thus removed itself from the natural order of things, it separated the Jewish Nation (represented by the last of the sephira-levels, which is nourished by the largesse of the lot of them) from G-d by virtue of the fact that things were no longer “in place”, as order and hierarchy are the ideal as we said, and “the more extraneous levels” were no longer “below the more exalted ones and … subservient to them”.
Not only that but “as soon as the husk took control of the sephira-levels the supernal light reversed itself”, which is to say that G-d’s presence hid itself, “the sephirot were no longer joined together, the Divine Flow diminished, and the Jewish Nation’s abilities weakened and lessened.”
And in fact that spiritual chaos and malnourishment is our situation in exile on an ethereal level.