The Gemara (Shabbos 88b) teaches in the name of R' Yehoshua ben Levi, "with every single statement that emanated from the mouth of the Holy One at Sinai the souls of the Jewish people departed from their bodies, as it is stated (Shir Hashirim 5:6), "My soul departed as He spoke". How did they receive the subsequent statements? Hashem brought down the dew with which he will resurrect he dead in the future and He resurrected them, as found in Tehillim (68:10).
I believe there are two profound lessons contained in this metaphysical teaching. The first is that Torah living engenders a different quality of life. To receive the Torah (aside from the physical preparations found in Shemos 19) they had to undergo a spiritual transformation; they could not be the same people that arrived at Har Sinai. The Zohar teaches that Hashem, His nation Israel, and His Torah are one. Thus, experiencing the prophecy of His Torah was a transformative infusion of Godliness. This is also indicated by the Talmud's (Shabbos 105a) understanding of the opening word of the Decalogue, "anochi", to be (in addition to its literal meaning) an acronym for "ana nafshi ksivsa yehivas", meaning that Hashem not only transmitted commandments to the Jewish nation, but gave part of His soul to them. As part of the dayeinu we praise Hashem not only for the content and teachings of Torah but also for bringing us to Har Sinai per se and inducing this transformation.
The Talmud (Shabbos 146a) further emphasizes this spiritual metamorphosis by stating that at Sinai "paska zuhamasan - they were purified", enabling them to receive their Sinaiitic souls. The Kuzari expresses this idea by stating there are five strata of beings - the inanimate, plant life, animals, man and Israel. The difference between each stratum is dramatic, including the difference between Israel, imbued with this Sinaniitic soul, and the rest of society. Being on this higher stratum enables us to imbibe Torah into our lives.
R' Eliyahu Lopian zt"l in his introduction to Sefer Shemos writes that the charge leveled by our enemies over the centuries that the Jew is too rich and successful is provoked by a middah that Hashem implanted in our nature: "One who loves money will never be satisfied with money" (Koheles 5:9); "If one has one hundred (units of money), he wants two hundred". This is understood by Chazal in a spiritual sense, that the Jewish neshama is drawn to the infinite. If this trait is not channeled positively towards spirituality, he will apply it to this-worldly affairs.
The second lesson that emanates from the resurrection at Sinai is the exciting concept of "marbeh Torah marbeh chaim - an increase in Torah increases life" (Avos 2:8). Why, one may ask, did the Jews' elevated souls depart after each commandment, necessitating a further act of resuscitation? Perhaps to teach future generations that although they attained one level of Torah and spirituality, they are still "lifeless" compared to the next level, and require Divine assistance to climb higher. "Saw you at Sinai" is not only a clever phrase to introduce/reconnect two singles, but the fact that all Jewish souls were present at Sinai means we each experienced this repeated revival. This experience not only enables us to constantly improve our quality of life, but also to become a fundamentally different person through increasing our Torah learning and observance of miztvos.
This concept emerges from a fascinating detail regarding the accidental murderer. The Torah teaches, "he shall flee to one of these (cities of refuge) and live" (4:42). The Talmud (Makkos 10a) rules that if a student establishes residence in a city of refuge his teacher must visit him regularly to maintain the rebbe-talmid relationship, as the Torah mandates "and he shall live", i.e. we must provide him with arrangements to be able to live. The Rambam (Hilchos Rotzeach 7:1) codifies this law stating that life without the study of Torah is akin to death. Given that the permanent residents of the cities of refuge were the Levi'im, whose role is to "teach Your ordinances to Yaakov and Your Torah to Israel" (Devarim 33:10), and thus there certainly was Torah and a Torah environment in the city of refuge, why do we specifically require that his teacher travel to the city of refuge to teach him Torah? Because without his teacher, the one that can inspire him and raise him as no one else can, he will not reach the same level of spirituality, and the absence of that achievement is called "lifelessness" by the Torah.
This is further substantiated by a fascinating dialog between R' Tarfon and R' Akiva (Kiddushin 6b). After a lengthy debate over a particular intriguing halacha, R' Tarfon concedes to the opinion of R' Akiva. When he took leave of him he said, "Akiva! Whoever separates himself from you it is as if he separated from life itself!"
The exciting teaching of the resurrection of the Jewish nation at Har Sinai gives new meaning to the prayer of Ahavas Olam (recited every night before reciting Shema Yisroel). There it states, "ki heim chayeinu - for they (Torah) are our life". This is to say that not only does Torah validate the Kuzari's designation of Israel as a class unto itself, but within the Jewish nation Torah gives each individual a daily opportunity to renew and upgrade their lease on life.