Our Gemara on Amud Aleph references a verse (Shemos 24:10) that describes the vision the Elders had at Sinai. There is a cryptic phrase, which I’ll do my best to translate:

וַיִּרְא֕וּ אֵ֖ת אֱלֹהֵ֣י יִשְׂרָאֵ֑ל וְתַ֣חַת רַגְלָ֗יו כְּמַעֲשֵׂה֙ לִבְנַ֣ת הַסַּפִּ֔יר וּכְעֶ֥צֶם הַשָּׁמַ֖יִם לָטֹֽהַר׃

⁦and they saw the God of Israel: under His feet there was the likeness of a brick of sapphire, like the pure blue sky.

Rashi on this verse records a touching Midrash, however it really requires more investigation to understand better:

The brick of sapphire was in front of God to remind during the travails of the slavery, i.e. the sapphire brick to remind Him of the Jewish suffering under the brick making quotas.

While this is a beautiful and sentimental piece, we need to analyze this further. The first question is, there must have been many kinds of sacrifices and miseries that the Jews put up with during the slavery and bondage. Why this? Why the bricks? Also, how does this really relate to the vision that the elders had at Mount Sinai? Was this the most important datum that God needed to reveal at that time? Nothing about the mysteries of the Universe? What about other great questions about the nature of God?

The Baal HaTurim notes that another commemoration of the brick quotas and slavery is referenced in Yehoshua (19:26). Apparently, a city was named Shichur Livnas, after the Brick making in Egypt. However this commemoration seems more relevant as the Jewish people who established their own cities might want to memorialize their past traumas and triumphs.

The Chasam Sofer on Chumash discusses the quality and meaning of sapphire in this vision, and perhaps based on that, we could understand the Rashi better as well. Chasam Sofer Explains that the Sapphire is of a clear quality, like the pure sky. Sapphire is still physical and material but at the most sublime level, given its physical limitations as matter. In particular, its quality is that it can take on any color because by itself it has no color. In the same way, the righteous are able to transcend beyond the angels. Angels can only follow their specific task, but a human can transcend to the highest level and become anything. The Elders at first thought that humans were like angels and had specific specialties that they could not transcend. Thus they thought Moshe represented punishment and justice and thought that Aharon should receive the Torah, since he represented mercy and shalom. The message of the sapphire was that Moshe could become anything.

From this idea I would like to explain the point of the bricks of slavery in the Elders’ vision was not merely to show that Hashem was with them in their suffering but to show that the Jews could transform. The same Jews that were molding physical bricks in Egypt could be the Jews to ascend to Heaven and see the heavenly bricks.