Observing Shabbat Like a Free Man Why are leaving Egypt and Observing Shabbat so deeply interwined?

Kiddush, Shabbat Evening. It was evening and it was morning. The sixth day. The heavens and the earth and all their hosts were completed. God finished by the Seventh Day His work which He had done, and He rested on the Seventh Day from all His work which He had done. God blessed the Seventh Day and made it holy, because on it He ceased from all His creative work, which God had created to fulfill its purpose. Attention, gentlemen, rabbis, and my teachers!
Blessed are You, Lord our God, King of the universe, who creates the fruit of the vine. (Amen) Blessed are You, Lord our God, King of the universe, who made us holy with His commandments, has desired us, and has given us, in love and goodwill, His holy Shabbos as a heritage, as a reminder of the Creation. It [Shabbos] is the first day of the holy festivals, commemorating the Exodus from Egypt. For You [God] have chosen us and sanctified us from among all the nations, and with love and goodwill given us Your holy Shabbos as a heritage. Blessed are You Lord, who makes the Shabbos holy. (Amen)]

Deuteronomy 5:13-15
(13) Six days you shall labor and do all your work, (14) but the seventh day is a sabbath of your God יי; you shall not do any work—you, your son or your daughter, your male or female slave, your ox or your ass, or any of your cattle, or the stranger in your settlements, so that your male and female slave may rest as you do. (15) Remember that you were a slave in the land of Egypt and your God יי freed you from there with a mighty hand and an outstretched arm; therefore your God יי has commanded you to observe the sabbath day.

Abraham Joshua Heschel, The Sabbath
Judaism teaches us to be attached to holiness in time, to be attached to sacred events, to learn how to consecrate sanctuaries that emerge from the magnificent stream of a year. The Sabbaths are our great cathedrals; and our Holy of Holies is a shrine that neither the Romans nor the Germans were able to burn . . . . The meaning of the Sabbath is to celebrate time rather than space. Six days a week we live under the tyranny of things of space; on the Sabbath we try to become attuned to holiness in time. It is a day on which we are called upon to share in what is eternal in time, to turn from the results of creation to the mystery of creation; from the world of creation to the creation of the world.

Shemot Rabbah (1:32) teaches that when Moshe lived in the palace, he observed that the Hebrew slaves had no opportunity for rest. Without one day of rest per week, he argued, Pharaoh’s slaves would die. Pharaoh was persuaded, and Moshe instituted Shabbat as their day of rest. An additional midrash (Shemot Rabbah 5:22) explains that the Hebrew slaves had in their possession various scrolls, relating the incidents of the book of Bereishit, which they would enjoy reading during their rest every Shabbat. They knew from these scrolls that Hashem would redeem them. Pharaoh, therefore, decreed the collecting of straw so that they would have no rest, and thus not be able to think of redemption. Hirsch notes that lo tosifun is spelled as if it said lo te’asfun, “do not assemble,” because the purpose of the decree was to disperse the slaves, to prevent any assembly in which such ideas as devotion to Hashem, redemption or human dignity could be discussed. Originally, Pharaoh understood that, as a day off, Shabbat would protect his investment. After all, even on their day off, slaves retain the self-image of slaves. But the Hebrew slaves had a glorious historical memory, an unshakable connection to Hashem, which they recalled on Shabbat, in repose and stability. The spiritual rejuvenation of Shabbat is a potent, subversive power against tyrants. Pharaoh, like many dictators throughout history, feared Shabbat. He knew that the key to undermining its effect upon the human spirit was to keep the slaves moving and to prevent them from assembling, so he decreed that every slave become a “mekoshesh.”