The name Devarim-Words, for the fifth book of the Torah, is somewhat unusual. It simply means words. Don’t all books of the Torah contain words? Indeed, while the other four books are G‑d’s direct communication, the Book of Devarim was spoken by Moses, albeit with Divine inspiration.
In truth, the fact that these are G‑d’s teachings channeled through Moses’ words is what makes this book unique.
Moses was not just repeating G‑d’s teachings to him; he was allowing G‑d’s thoughts to become internalized within his own mind, which allowed him  to transmit these teachings to us in a way that is relevant, meaningful and transformative to us.
Without Devarim G‑d’s teachings of the first four books would have remained detached from our consciousness. The message would have been inaudible. We could not have processed such sublime ideas.
G‑d’s teachings were introduced into the realm of words that affect us when they were channeled through Moses’ words that were audible to us.
Moshiach, however, will take this process to the next level. He will channel G‑d’s knowledge through the visual medium. We will not just hear
G‑d’s words, we will see them!

  Moses’ Added Blessings
In a last soliloquy before his passing, Moses prepares the Jewish nation for its entry into and conquest of the Land of Israel.
Moses then blesses them:
May G‑d, the G‑d of your forefathers, add to you a thousand times yourselves, and bless you as He has spoken to you.”
Rashi explains this rather cryptic verse:
The people of Israel said to Moses [who blessed them with a thousand time blessing]: “Moses, you are putting a limit on our blessings! The Holy One, Blessed is He, has already promised Abraham ‘so that if one can count [the dust of the earth, then your offspring too, can be counted’”]. Moses said to them, “This [blessing] is my blessing, but He shall bless you as He spoke to you.”
In other words, the people complained, why did Moses offer to bless them with a thousand-fold blessing, which is limited, when G‑d had already promised them unlimited blessing?
Moses’ response was that his blessing was not in place of G‑d’s blessing but on top of G‑d’s blessing.
This obviously requires clarification.  Many of Rashi’s commentators note:  
If G‑d has already given unlimited blessing to the Jewish people, what can anyone, even Moses, add to that? It’s like lighting a candle in broad daylight; it doesn’t contribute to the light.
It sounds like the joke that is told about two beggars who were imagining that they would acquire Rothschild’s wealth. One of them said, “if I had Rothschild’s wealth I’d be even richer than Rothschild.”
“How so?” his colleague asked.
“I’d do some begging on the side”…
Conditional and for the Future
Commentators answer that G‑d’s unlimited blessing was conditioned on observance of the commandments, whereas Moses’ limited blessings were given unconditionally.
Another approach is that Moses’ blessing was for the here and now, whereas G‑d’s infinite blessings were intended for the Messianic Age.
The Rebbe (Likkutei Sichos, volume 19) answers at length that the ultimate goal is to have the unlimited blessings fused with the limited blessing; so that one can access unlimited blessing within the confines of a finite source of blessing.
This, the Rebbe explains, is the very purpose of existence. G‑d created a finite world with finite capabilities, so that ultimately the transcendent aspects of G‑d shall come within our grasp and reach.
To explain:
G‑d has two ways in which He manifests Himself within Creation. G‑d is both a transcendent G‑d and an immanent G‑d, i.e., the infinite G‑d identifies with and is cloaked within the confines of a temporal and physical world.
The Dichotomy
Normally these two manifestations of G‑d operate on different wave lengths. When we see G‑d’s role in nature it appears very different from the way we see G‑d when He operates through miracles. When we see the laws of nature operating we don’t see the supernatural manifestations of G‑d. And, conversely, when we see miracles we don’t see nature. For example, when the Jewish people ate manna in the desert for 40 years, they did not see the natural process of food production. They were only privy to the supernatural phenomenon of food coming from heaven.
Upon deeper reflection, both manifestations are in effect limited; they both operate within and conform to their own system. Even the apparently unlimited and transcendent power of G‑d to override the boundaries of nature has its own boundaries; it cannot coexist with nature. We either have the natural world or the supernatural world.
However, the objective is to change that dichotomy and to allow both forces to meet.
The method through which we are able to make the transcendent immanent and bring about this synthesis, we are taught, is through the fulfillment of the Mitzvos.
Uniting Opposites
This leads us to a follow-up question:
How is it possible for two opposites, such as the finite and the infinite, to coexist? It’s like trying to jam a round peg into a square hole. To be sure, one with supernatural powers can find ways of squeezing the round peg into the hole by instantaneously changing the contours of the peg, or expanding the hole miraculously. But how can this feat be accomplished without altering anything?
The Talmud alludes to this conundrum when it illustrates the impossibility of having an elephant pass through the eye of a needle. It is so impossible that a sane person would not even imagine this scene in a dream. A miracle worker, on the other hand, can do it by putting the elephant on a crash diet and drastically or instantaneously reducing its size or by miraculously expanding the size of the eye of the needle to allow room for the elephant to go through.
But it is impossible to fathom how the elephant, in its present colossal size, can fit through a truly tiny opening of the needle, without altering the limits of either. These are impossibilities.
G‑d however can do that because G‑d’s essence transcends both the natural and the supernatural, the transcendent and the immanent, the finite and the infinite. G‑d transcends the rule of logic as well, and what is impossible to us is not impossible for G‑d.
Synthesis of G‑d’s and Moses’ Blessings
When Moses added his own blessing to G‑d’s blessing this was an example of G‑d revealing His true essence, through which the infinite and the finite can meet and be synthesized.
This dynamic, as the commentators cited above state, will only occur in the future Messianic Age. That will be the age when all of the filters that conceal G‑d’s essence will be removed.
Preparing for the Future
How can we prepare for such a phenomenon, where the supernatural and the natural meet? It is axiomatic that everything which will occur in the Messianic Age depends on the actions we take during the pre-Redemption age. What can we do today that will express the synthesis of the infinite and the finite?
The Rebbe explains that every Mitzvah we do is actually that very synthesis.
A Mitzvah is G‑d’s will. G‑d is infinite and so must His will be infinite, for as Maimonides asserts, G‑d and His attributes are one.
On the other hand, to perform a Mitzvah one requires a finite object, such as Tefillin, Talis. Mezuzah, kosher food, or money for charity. Those physical objects, although finite, unleash G‑d’s infinite light through the fulfillment of His will.
Hence, by Mitzvah observance today we pave the way for the ultimate synthesis that we will behold with our eyes of flesh following the imminent arrival of Moshiach and the Final Redemption.
To summarize:
We have three interconnected answers to why Moses’ limited blessing was added on to G‑d’s unlimited blessings:
First, G‑d’s unlimited blessings depend on our fidelity to the commandments.
Second, G‑d’s infinite blessings will be revealed in the future.
Third, the goal is to unite and synthesize the two sources of blessing, the one infinite and the one finite. This is in accordance with G‑d’s plan.  The transcendent aspects of the Divine will be fused with the immanent aspects of G‑d; the infinite will be revealed and absorbed within the finite.
In truth, these three explanations are interconnected. The syntheses-dynamic that fuses the infinite blessings of G‑d with the finite blessings of Moses is inherent in the performance of every Mitzvah. However, while we create this synthesis now, it will not be on full display until the Final Redemption.