Regarding this Shabbat, Shabbat Chazon (so named because of the Shabbat Haftarah, which begins *Chazon Ishaiyahu...*), there is a teaching from Rabbi Levi Yitzchak of Berditchev, of blessed memory, that on Shabbat Chazon, the Third Temple is revealed to each of us. The word *chazon* means vision. In Judaism, there are no coincidences. Everything has a meaning and a specific order. The Parashah Devarim is always read on the Shabbat before the 9th of Av (the day of the destruction of the two Temples, among other calamities), Shabbat Chazon. Therefore, there must be an intrinsic connection between these two matters (Parashah Devarim and Shabbat Chazon). According to this teaching, we will understand the connection.
The Mishneh Torah, the retelling of the Torah of Moses, begins with the parashah Devarim. One of the differences between the first four books of the Torah and the last is that Devarim was written for the generation that entered the Land of Israel, so it was necessary to warn them about certain matters relevant to it.
The difference between the generation in the desert and the one that entered the Land of Israel is that the desert generation was characterized by its knowledge; they were at the spiritual level of Moses, who had contact with God in the form of a vision. On the other hand, the generation that entered the Promised Land, because they had to engage with the physical world (plowing, sowing, harvesting, etc.), was automatically at a lower spiritual level. They had hearing.
The difference between "sight" and "hearing" is that when one sees something, it is infinite; that is, nothing can introduce doubt about it because one has seen it oneself. However, in the case of "hearing," when one hears something, even though at the moment of hearing it one is clear in reason, through questioning one can begin to doubt its veracity. This demonstrates that, even at the moment of hearing and internalizing it, the matter was limited.
That is why in the Mishneh Torah, which was given to the generation that entered the Earth, which was at the spiritual level of *hearing*, it was necessary to warn about topics such as self-sacrifice, while it was not imperative to warn about the same topics to the generation of the desert.
However, there was an advantage in the generation that entered the Land, which is why it is written about the generation of the wilderness *because they did not come now to peace and inheritance* (Deuteronomy 12:9), which refers to the Tabernacle of Shiloh and the Temple of Jerusalem, which were only erected once they entered the Promised Land.
Kabbalah explains that *The beginning is linked to the end*. It is specifically at the lowest levels, in the physical and material world, where the essence of God can be found. That was the advantage of the generation that entered the Land of Israel, because only through descent, through involvement in physical and material matters, could they reach their goal: peace (Shiloh) and inheritance (Jerusalem).
The Shabbat of Parashat Devarim indicates the union of two opposing matters: 1) it is a great descent (involvement in material matters). 2) through that descent one reaches a true elevation (the essence of God).
The same concept is expressed by Shabbat Chazon, which contains two opposing extremes: 1) it is part of the nine days during which the Temple in Jerusalem was destroyed; 2) it is through destruction that the ultimate elevation will be achieved, as mentioned in the name of Rabbi Levi Yitzchak of Berdichev, of blessed memory, that Shabbat Chazon shows us the Third Temple, which is higher than the previous two, to be swiftly built in our days through our Righteous Messiah.