Our Rabbis (Talmud Yuma 29a) teach us that the night is darkest right before dawn. Similarly, right before the actualization of the four l'shonos ha'geula, the Egyptian servitude was at its most oppressive point. The Torah teaches that "v'lo shomu el Moshe", they could not listen to Moshe and his optimistic promise of deliverance, m'kotzer ruach, and avodah kasha - due to their shortness of breath and hard work.
Rav Yaakov Kaminetsky zt"l (in his Emes L'Yaakov) has an additional explanation. The Medresh Shemos Rabba (5:22) teaches that Bnei Yisrael in Mitzrayim had megillos - texts that they studied every Shabbos that helped them maintain their emunah/bitachon in their being redeemed, but we are not told what the contents of these megillos was. Rav Kaminetsky opines that they contained those pirkrei Tehillim that were composed by Moshe, as we are taught in Bava Basra (14b) that Moshe composed Teffilah L'Moshe (Tehilim 90) and the next eleven perakim, including Mizmor Shir L'Yom Ha'Shabbos. It is most intriguing to note that perek 92, a song for the Shabbos day, has no reference to Shabbos nor to the mitzvos or character of the day. However, it does contain the important answer to the question of tzadik v'ra lo - namely, why do the wicked prosper and the righteous suffer? We are assured that while evildoers enjoy temporary success, it is only that they may be eventually destroyed forever. The psalm ends with the assurance that the righteous will flourish as a palm tree, and that Hashem is my rock, in Whom there is no wrong. It is this psalm and others that maintained Bnei Yisroel's faith.
Initially, "Yismach Moshe b'matnat chelko" - Moshe convinced Pharoah to give the Hebrew slaves a day of rest and Moshe chose Shabbos, which gave them not only physical rest but also a weekly spiritual injection of faith. However, as taught at the end of Parshas Shemos (5:9), when Moshe asked for the liberation of the slaves, Pharoah intensified their servitude, which included their loss of Shabbos and thus, explains Rav Yaakov, they were losing faith and could not listen to Moshe.
Shabbos, since time immemorial, has been the bastion of our faith. Every Friday night we fulfill the biblical mitzva of kiddush, and in it there are two remembrances: a remembrance of the work of creation, and of the exodus from Egypt. The Ramban (Devarim 5:15) teaches that these are not two independent themes, but rather the Exodus proves Creation. The fact that Hashem demonstrated complete and total control over nature, providing water for the Hebrews and blood for the Egyptians, sending wild animals that could distinguish between Egyptian and Jew, etc., all showed that "Ani Hashem b'kerev ha'aretz" (Shemos 8:18), that He is not only the Creator-Boreh, but the Ruler-Manhig over all creatures.
Regarding Yeztiyas Mitzrayim, the Seforno (Shemos 12:26-27) teaches a most exciting concept. He understands the question of the ben ha'rasha of "ma ha'avoda ha'zos lachem?" to be asking why is the korban Pesach a korban yachid, an individual's korban, as opposed to a communal one? His answer is that each individual has to bring their own sacrifice since the miracle of the Exodus happened to each individual, not only to the nation as a whole. It is one thing to say, for example, that the Egyptians had blood as a result of the first plague and the Jewish people had water. That would be understood as a miracle for the nation. However, we are taught that if an Egyptian and a Jew were drinking from one glass, at the very moment that the former drank blood, the Jew drank water - thus demonstrating a personal miracle for that individual. Moreover, Chazal teach (on the verse Shemos (14:30) that not only did the Jewish nation see the Egyptians dead on the seashore, but that Hashem washed onto the shore in front of each Jew the very cruel taskmaster who had tortured him. Again, a personalized miracle for each individual.
Just as Yetziyas Mitzrayim has these two components of personal and communal, so too does Shabbos. On the verse (Shemos 31:16) "V'shomru Bnei Yisrael es ha'Shabbos la'asos", the Or HaChaim teaches that the first half of the verse refers to the obligations of each individual to honor and guard the Shabbos, while the second part, "la'asos", imposes the obligation to see that the community as a whole keeps the Shabbos.
Regarding the individual obligation to observe Shabbos, I'd like to suggest that as Shabbos uplifted and strengthened the emuna of the Jews even before the Exodus, Shabbos forever adds to our religious growth and connection to Hashem. This is done by zachor, the positive actions of preparing for and observing the holiness of the day, by dressing properly and eating and studying of Torah, and shamor, i.e. by yielding to His restrictions we consciously imbibe His being the Master of the universe.
In addition, as the Exodus clearly demonstrated His hashgacha pratis, His involvement in the life of each individual, so too on Shabbos we are to pause and reflect on this phenomenon. While we acknowledge and extend thanksgiving to Hashem thrice daily in the bracha of modim in Shemoneh Esrei for the personalized miracles that He performs for us, too often it is said in a hurried and hectic environment. The peacefulness of Shabbos provides the ambiance for a more deliberate focus on the personal relationship that we each are blessed to have with Hashem.
The singing of Shalom Alechem of Friday night is universal. After that, appropriately we sing Eshes Chayil in honor of the Shabbos Queen and the queen of the household who creates the holy atmosphere that envelops the home on Shabbos. I was fortunate that every Shabbos in between these two my father z"l recited the prayer entitled "Ribon kol ha'olamim", a beautiful tefillah admiring the personal relationship we are privileged to have with Hashem. Including therein is, "I thank you, Lord my G-d, and G-d of my ancestors, for all the loving kindness that You have done and will do for me, and all the members of my household and all my fellow creatures". I strongly recommend that as part of the Shabbos meal, aside from the zemiros and divrei Torah, each of the participants in the meal should share an experience or occurrence whereby they saw His Hashgasha Pratis in their day to day living in their past week. This will help them focus and realize His personal involvement in their life.
The Or HaChaim teaches on the verse "va'yivarech Elokim" (Bereishis 2:3) that Shabbos provides blessing and energy throughout the week. May the focus on His personal relationship with us not only enhance our individual Shabbos, but strengthen us to influence others to keep Shabbos as well. Similarly, the Ramban, in his famous commentary at the end of Parshas Bo, teaches that from the open great miracles we learn to appreciate the small daily miracles as well. The Creation and the Exodus are clearly the two greatest and overt miracles which are the bedrock of Shabbos, and hopefully will assist us in appreciating His personal involvement in our lives.
We are living in most extraordinary times. It is hard to absorb but 800,000 Americans have died from Covid. This is clearly a living implementation of "Yoshev b'seser Elyon" (Tehillim 91), where we are taught "a thousand may fall at your side, ten thousand at your right hand, but it will not come near you." "Thank you, Hashem" is not only the way a Jew begins his day with Modeh ani, but is also the very adrenaline that keeps him going strong throughout the day.