The fourth of the Ten Commandments is that we must remember and observe the holy day of Shabbos. The institution of Shabbos is so that we remember that G-d ceased from creative activities on the seventh day of creation. In addition, the Torah states that it is a remembrance of our servitude in Egypt.
The great commentator Tosfos quotes a Medrash which explains the link between the servitude of the Jews in Egypt and the Shabbos: The Pharaoh forced the Jews to perform 39 types of work. When G-d gave us a day of rest, He forbade us to perform those 39 activities that the Jews were forced to work while they were enslaved. Our observance of Shabbos is thus also a remembrance of the forced labor of our ancestors, and by ceasing from these activities on Shabbos we recall our deliverance from Egypt.
The Medrash relates that originally Pharaoh enslaved the Jews 24/7. However, Moshe, who was clandestinely raised in Pharoah’s palace, and would eventually become our leader, suggested to Pharoah to give the Jews a day off. Moshe’s selling point to Pharoah was that he would benefit from the Jews resting for a day so that they would be able to rejuvenate themselves and work more efficiently.
Pharoah agreed, and asked Moshe which day of the week he would suggest to give them off. Moshe told him the seventh day of the week. Thus, the Jews were off on the day of Shabbos.
The Medrash relates that after the redemption when G-d told Moshe of the special gift of the holy day of Shabbos He was giving to the Jewish people, Moshe was elated that he had chosen the appropriate day for the Jews to have off. In the Shabbos day Amidah prayer we capture Moshe’s delight when we say, “Moshe was overjoyed by the special gift of his.”
Each of the plagues that G-d brought upon the Pharoah and the Egyptians lasted for seven days. The great commentator, Baal Haturim, points out that during the plague of locust the Torah uses the word, Vayanach. This is the same word the Torah uses on the Seventh day of creation to describe that G-d rested. Says the Baal Haturim, this teaches us that the locust rested and did no damage to Egypt on the Shabbos in the midst of the plague.
The Divrei Yoel quotes a source that during the six days the plague of darkness descended upon the Egyptians, the darkness was lifted on the day of Shabbos. He says that we can bring proof to this from the Ramban who says that the eighth plague of locust began on Rosh Chodesh Nisan and concluded on the 7th of Nisan. The next plague was darkness which came without warning, thus the darkness began on the 8th of Nisan. The third day was the 10th of Nisan which we know was Shabbos. On this day the Jews were instructed to take a sheep or a lamb into their homes and tie it to their bedpost to inspect it for four days to make sure it was unblemished and fit for the Pascal sacrifice.
The lamb and sheep were the Egyptian’s deity and were always free to roam. The Talmud tells us that when the Egyptians saw the Jews take their deity into their homes and were told of G-d’s instruction to sacrifice it, they were appalled, but they were powerless to do anything. That Shabbos is referred to as Shabbos Hagadol – the Shabbos of the great miracle.
Had the plague of darkness been employed on the Shabbos, how would the Egyptians have seen the Jews take their deity into their homes? It must be, that the plague was paused in honor of the Shabbos.
The darkness continued on Sunday, Monday and Tuesday. The Talmud tells us that the plague of darkness was beneficial for the Jews, for during this time the Jews who did not want to leave Egypt died, and because of the darkness the Jews were able to bury their dead without the Egyptians able to see what was going on. Also, during the darkness the Jews were able to snoop around and locate all the places where their masters hid their treasures. However they did not take a single thing.
For this reason also, darkness was unnecessary on Shabbos, since handling a corpse and burying the dead is forbidden on Shabbos.
On Wednesday, the 14th of Nisan, the Egyptians eagerly presented their riches and clothing to the Jews. That evening the Jews slaughtered the Pascal lamb. They dashed the blood on the inner lintel and two doorposts of their homes and the Jews were instructed to stay indoors and not leave their homes the entire night. During the night they were dressed as if they were ready to leave. The pascal lamb was roasted and each Jew ate a piece together with Matzah and Morror. They concluded their Seder by midnight. Precisely at midnight G-d personally smote the Egyptian firstborn and passed over the Jewish homes. Pharoah frantically began looking for Moshe and Aaron to lead the Jews out.
G-d waited until the next day and during broad daylight on Thursday, the 15th day of Nisan, He simultaneously took and freed the entire Jewish nation by airlifting them at once to a place called Succos. They began their journey from there.
When the plague of darkness descended upon the Egyptians, the Torah tells us that the Jews had light in all their dwellings. Tiferes Shlomo points out that within the Hebrew word for dwellings, are the letters that spell the word Shabbos. The Jews were not only unaffected by the darkness, they actually were enveloped by a special Ohr – light/aura. Imrei Emes explains that with every Mitzvah that a person performs or heeds, he is encased by the aura of the Mitzvah. This gives him the ability to correctly navigate and perceive what is just illusionary, and what is authentic, beneficial and enriching.