When a person poses a riddle, because he knows the solution, all of the complexities of the riddle are clear to him.
For him, the question and the solution are one.
But the person to whom he poses the riddle is in a different place.
This person experiences concealment, a thick curtain separating the riddle from its solution.
Both people are involved with the same question; but to one, it is completely opaque.
To the other, it is completely transparent.
For all the "contractions" and "garments" are not things distinct from Him, Heaven forfend, but "Like the snail, whose garment is part of his body:'
A person's clothing is not a part of him; he can put it on or take it off as he wishes.
But the snail's "garment;' its shell, is an inseparable part of it and is integral to its essential nature.
In this sense, the garments of divine light are also a part of the divine being.
Concealment and constriction are as much a revelation of God as are what we usually understand as revelation and manifestation–"darkness is like light."
–Rabbi Adin Steinsaltz
From Learning from the Tanya, Chapter 21, by Rabbi Adin Steinsaltz