Thus the above-quoted phrase -- "G-d's infinite light extends ... downward without end" -- refers to its revelation and utterly boundless diffusion even as it is revealed at the lowest levels of creation.
The infinite worlds that precede the tzimtzum, and [even] the World of Atzilus, where the infinite light shines overtly, are vessels [i.e., have the capacity] for receiving the infinite light, for the vessels themselves are G-dly.
No wonder, therefore, that the infinite light shines there overtly, or that they are able to receive it.
The [more limited] Worlds of Beriah, Yetzirah and Asiyah, however, are lower.
For the vessels of the World of Atzilus are as the body to the soul, while the vessels of these three Worlds are like garments.
As it is written in Pasach Eliyahu, "You have made garments for them" -- a reference to these three Worlds, which are only garments enclothing the light of the vessels of Atzilus (which are described as bodies).
It is similarly written, -- "The Supernal Mother (i.e., the attribute of Binah in the World of Atzilus) nests in the realm of the throne (i.e., the World of Beriah); the Six Sefiros [i.e., Ze'eir Anpin, the Divine `emotive' attributes] are situated in the World of Yetzirah; and Ofan [i.e, the Sefirah of Malchus] in the World of Asiyah."
Since these three Worlds are only garments for the light of Atzilus, they are called the lower realms.
The above-quoted statement [from Pasach Eliyahu] about the garments of these three Worlds continues: "From them souls issue forth to man."
Most souls emanate from these worlds.
Only one soul in a generation, [and then, only] in the early generations, derived from Atzilus.
In fact there are three levels of emanation from these three Worlds: souls emanate from their innermost aspect; angels from their outer aspect; and worlds from their outermost aspect.
By means of the successive stages in the chainlike scheme of spiritual descent that is called hishtalshelus, the light of these three Worlds becomes increasingly obscured. When it reaches the realm of the Galgalim and Mazalos it becomes dense and more material.
This descent allows the Galgalim and Mazalos to monitor the influence and revelation of the Divine light in this lowly, material world.
This function is alluded to in the verse, --"From the rich harvests brought out by the sun and the rich produce hastened forth by the moon."
Another reference to this subject is to be found in the statement of the Sages, -- "No blade of grass below is without its Mazal Above that strikes it with the command: Grow!"
[The world, then, is animated] by the G-dly light and life-energy that flows through the Galgalim and Mazalos. It is a far-reaching condescension for G-dliness to appear in such a concealed manner, through the many downward stages represented by the worlds of Beriah, Yetzirah and Asiyah, to the point that it is expressed in external, material influences.
This is particularly true as G-dliness descends through many tzimtzumim and many stages of concealment until it [becomes enclothed in a creation that outwardly] is the very opposite of G-dliness. There are beings [of the physical realm] that can (G-d forbid) entirely forget G-dliness.
This we see in the forces of evil [whose approach is epitomized in Pharaoh's boast], "The Nile is mine, and I have made it."
This was the very opposite of the truth. For it was Yaakov who blessed Pharaoh, and (as is stated in Midrash Tanchuma and cited by Rashi on the appropriate verse) his blessing was that the Nile should rise at Pharaoh's approach -- an instance of the Divine good being drawn down to this world.
Pharaoh, however, was the King of Mitzrayim -- a word which means "Egypt" when vocalized one way, and which means "constriction" when vocalized differently.
[Being thus the very archetype of a limited, nonspiritual conception of the universe,] Pharaoh was not only ungrateful, but claimed furthermore, "The Nile is mine, and I have made it."
Parallels to this attitude may be detected in the divine service of every man, whether he be a businessman or a scholar.
In the world of business a man may incline to think, -- "My strength and the might of my hand have made me this wealth."
Even though the same man knows and believes that [in the words of the following verse] "it is [G-d] Who gives [him] the power to accumulate wealth"; even though he knows and believes that "it is the blessing of G-d that grants wealth"; even though he mentions the Name of G-d at every stage in his business dealings; -- nevertheless, he may still think that it is the might of his hand, his own intellectual superiority, that is responsible for his prosperity.
When success smiles upon him, therefore, he is prone to "grow bold in his wickedness," becoming inflated with pride in the fruits of his wisdom.
On the other hand, when his fortunes are bleak, such a man's spirits will fall, and he will become depressed. In fact, however, both these reactions are unjustified.
For since "it is the blessing of G-d that grants wealth," he should experience equanimity in the face of both situations. And if his affairs have not succeeded, let him seek a fault in himself.
Similarly with one of those who "dwell in the tents" of scholarship.
Even though while he is at his books he keeps in mind that this is G-d's Torah that he is studying, it is always possible that in the name of the Torah he will render a legal decision that contradicts it.
In this he resembles the above businessman who, even though he believes with simple faith that "it is [G-d] Who gives [him] the power to accumulate wealth," and even though he believes that "it is the blessing of G-d that grants wealth," nevertheless grows buoyant and opinionated when his affairs are doing well...and bothered and crestfallen when times are hard.
The reason for these feelings is that his business stands on a mistaken foundation. His belief that "it is [G-d] Who gives [him] the power to accumulate wealth" is [not internalized, but rather] left at the level of simple faith; the principles guiding his business transactions, however, do not conform to the standards set by the Torah. And this explains the untoward results described above.
In similar fashion, though a scholar knows that what he is studying is G-d's Torah, the very essence of his study and his knowledge may be faulty.
Even while studying the Torah he may forget the Giver of the Torah.
His study can become a mere intellectual exercise, so that even though he may well know what he has mastered, he may later follow the dictates of his independent intellect and arrive at conclusions that contradict what he has studied.
The same pattern may be observed on a wider scale.
Though a person may receive his life-energy from G-d Himself, it is possible for him [to conduct his life in a manner that] contradicts G-dliness -- because the light filters down to him through an abundance of tzimtzumim and stages of concealment.
In the Holy Tongue this is hinted at in the very word for "nature" (teva), which shares a root with the verb "to sink," as in the phrase, -- "sank in the Sea of Reeds."
Like something that sinks out of sight, the descending G-dly light becomes increasingly obscured until it reaches even the lowliest levels of creation.