The significance of Shabbat is so great that it is equal to all the other mitzvot of the Torah, and its observance entails great reward.

The Holy One, blessed be He, said to Israel: If you are privileged to observe Shabbat, I will consider it as though you have observed all the mitzvot of the Torah; and if you profane it, I will consider it as though you have profaned all the mitzvot. Likewise it is stated: “Who keeps the Sabbath from its desecration and stays his hand from performing any evil” (Isaiah 56:2).

Rabbi Hiyya bar Abba said in Rabbi Yohanan’s name: Concerning anyone who observes Shabbat in accordance with its halakhot, even if he worships idolatry as in the generation of Enosh, God forgives him his sins.

Rav Yehuda said in Rav’s name: Had Israel properly observed the first Shabbat, no nation…would have ruled over them, as it is stated: “It was on the seventh day, some of the people went out to gather” (Exodus 16:27), and it is written afterward: “Amalek came and made war with Israel in Refidim” (Exodus 17:8).

Rabbi Yohanan said in the name of Rabbi Shimon ben Yohai: Were the Jewish people to observe two Shabbatot in accordance with the halakha, they would immediately be redeemed. (Shemot Rabba 25; Shabbat 118b)