When a person thinks deeply [hisbonenus] [about G-d], there are different types of excitement in his mind, heart, and thought, according to the 5 levels of the soul. This was explained in a pamphlet. Now we have to explain this thing called deep thought. What is it, really? And what should you think about?

To think deeply is to stare intently at the depth of the idea, and to stay with it until you understand it with all of its details. It is the inner meaning of Binah [lit. understanding]. The Talmud calls it iyun, like it writes in Tractate Sukkah, "There is girsa and iyun".

The depth is like the depth of a river. It broadens from there, but [the depth] itself isn't wide at all. It is the true self of the river (which is called the current), the main flowing from its source. The waters above it and to its sides are secondary. They're just that power spreading out, to the sides (the width of the river), in the height, and the length that it flows.

So too, the depth of the idea [muskal] is the point itself, as it is. It is called the depth of the idea [musag]. Many things spread out from it. It goes to all sides, with a great width, with many details. It [travels along its] length, with a huge descent. It even goes up, reaching a higher level [of knowledge] then it had before.

(Until the high depth [omek rom], like the waters of the Mabul which flooded above everything. A similar thing will happen in a spiritual way in the 600th year of the life of Noach, as it writes in Zohar that "the wellsprings of wisdom will open up etc". This is talking about the deepest wellsprings [mayanos tehom] of chochma, that will flood above everything and cover the mountains. "And the windows of the heavens will open" to draw down from the water above the heavens which is called the high depth. [These waters] depend on the lower depth because "the end is wedged into the beginning". Like "[cast] deep your question, or raise it up high", and as is explained in [other] writings.)

All of this is drawn from the real depth-point itself, as it is drawn from chochma which is called "nothing [ayin]".

This is called "iyun". You sit with the idea, and look into it a lot. This is a slowness, the opposite of swiftness. It brings you to the inner depth of the idea specifically, as it really is.

Like if you stare at something. Not just glancing over it, but focusing and sinking your eyes. Slowly and carefully, until you know it through and through.

This is called hisbonenus[התבוננות], with a doubled nun [ננ] [hinting to repeated study]. You think and look into it a lot. Like Rashi explains, "With iyun - to sit with the idea, to understand it with all of its details."

[It's true that] chochma is the nothing [ayin] of the idea, even before it becomes the depth of the idea in bina [depth of the musag] [which has details]. [Chochma is] the wellspring compared to the river, as was mentioned earlier. Still, that wellspring has a source. And when you delve into the source of the chochma idea [muskal], you reach that [deeper] source which feeds the wellspring of chochma.

[That deeper source] is called the depths of chochma, or the secrets of chochma. Just like there's depth, length, and width in bina (which is called a something [yesh]), so too there is depth, length, and width in the wellspring of chochma (which is called a nothing [ayin]).

The depth of the wellspring is the beginning of its source underground [the aquifer]. Its flow spreads out from there, higher and higher, until it breaks through [the surface]. Drop by drop, it becomes revealed from where it was hidden. Its ultimate hiding is in its ultimate depth. Like [the paraphrased verse about Noach's flood], "[The] wellsprings of the great depth broke out [from the depths, where they were concealed]." The earth is full of tunnels [of water] - veins, which are the first depth.

This is what [we mean when we] say "chochma [comes] from nothing [ayin]" - from the hidden chochma, which is called the depth of chochma. Chochma is the birth of a new idea, which is like a flash of lightning, as is known. Its source, in its concealed depth, is its real, innermost self.

However! The depth of the idea [musag][of bina] (which is called the 50th gate [shaar ha'nun] of bina) - yes, it's drawn from the nothing of chochma to be a something. (Like "A wellspring goes out from the Holy of Holies [in the Temple]. It starts out [small] like the horns of a grasshopper etc.", and other writings like that.) But its root reaches into the depth of chochma.

And we see this all the time. The one who delves deeply into the depth of the idea [musag] [of bina] - he is the one who reaches the source of the idea [muskal] [of chochma], to bring out new things from the light of chochma into bina. This process is called delving [maamik], which is a causative verb [mafil], because it activates the depth of chochma and bina.

"Use bina with chochma" (ס"ג דע"ב) is chochma's own ability to explain [the idea] from many different angles. This is still higher than bina's grasp.

[The Talmud] says that "Men of understanding [nevonim] weren't found". [A man of understanding is] someone who understands one thing from another thing. That is from the root of this power (of using bina with chochma). [The root] can reach in to the depth of chochma. That's why [he's able to use] this topic to understand an entirely different topic.

What people call "the delving of daas" - this isn't the actual delving [into the idea], like the depth of the grasp of bina. That has no connection to daas.

Daas is connecting, and really caring for the idea. It bring to a deeper understanding of the idea- [but only] after iyun, which is like a vessel for the depth of the understanding.

Here's the difference between people who have light daas and deep daas, between adults and children. A child whose daas is light doesn't have the ability to care for and relate to what he understands or wants. Only in a very superficial way. It's easy to convince him to completely change his mind.

When an adult has a deep daas into something that he understands or wants, we call that "the delving of daas". Length and width automatically come from that, like it was explained before about bina.

The sign of delving with daas is that you're strong, deep connection to the idea makes it look like you're squeezing your brain. (In Yiddish - he is captivated by the thing, all tense, to the point that he's all bound up, only [expressing himself] in a movement, or a glance). Deep understanding comes from this when there is iyun of bina, which is the opposite of limiting and intense focus [on one thing].

With iyun you also take your time with the idea, pushing yourself and focusing. But that's only the beginning. Immediately it spreads out very broadly to the particular parts, identifying everything very particularly.