In the process of apprehending a concept, the mind first "grasps the concept,” then "encloses it with its intellect,” and finally "enclothes" it.
The grasping of the concept is the initial contact between the mind and the concept it conceives, the "point of chokhmah".
The mind's enclosing of the concept–as opposed to merely "touching" the idea on one side–occurs in the stage of binah ("comprehension"), in which the object of the mind's interest can be said to exist within the mind and be encompassed by it.
Binah is not a point but a process.
At first, the mind only touches the concept tangentially.
And as the comprehension progresses, the mind covers more sides of the concept, until it completely encloses it and relates to its every facet.
When comprehension is complete, so that the idea is totally enclosed by the mind, the idea can now go on to be applied to other ideas.
This marks the point at which the idea is "enclothed" by the mind.
A garment is the medium by which a thing relates to realities outside of itself.
Thus, when we say that the mind enclothes the concept, this means that the concept can now be further extended, that the mind can now serve as the garment by which it is related to other concepts.
This is the basis of the assumption that the inability to explain something well shows a deficiency in understanding.
There are other factors, not connected with understanding, that interfere with the ability to pass things on, such as difficulty in communicating.
But a true and full explanation is not possible without a full understanding, whereas a person who "truly and fully" understands, something will inevitably find a way to pass it on.
At the very same time that the mind en clothes the concept and encloses it within itself, an opposite process also takes place, in which the mind is itself enclothed within the concept.
Just as the mind is serving as a garment for the concept (that is, as its medium of expression and relation, as well as the screen that obscures its essence and allows only a certain expression of it to be manifested), so, too, is the concept serving as the garment of the mind.
For when a mind is involved and absorbed in a certain subject, it expresses itself at that time through that concept.
One can thus say that the mind is enclothed in the concept it is contemplating, for it is now manifesting itself through this particular garment, and the garment is obscuring its quintessential qualities.
In other words, the mind is now not a mind per se but a mind as expressed through the particulars of the concept within which it has invested itself.
The mind is not only thinking the idea, it is also being "thought" by it, in the sense that the mind is now perceived exclusively in the context of the particular idea.
This is true of every mind and every concept at any level, from the simplest to the most advanced and complicated.
The process of thought is always a process in which the mind and the object of its contemplation enclose and are enclosed by each other.
–Rabbi Adin Steinsaltz
From Opening the Tanya, Chapter 5, by Rabbi Adin Steinsaltz