What was the importance of Sabbath?

The Sabbath is an ancient Jewish tradition taken from the books of Genesis and Exodus. When God created the earth, as accounted in Genesis, he labored 6 days and on the 7th, he rested. He did not do this because he needs rest, but more to set the example for the Israelites to come. When Moses took the Israelites out of Egyptian slavery and they sojourned in the wilderness, God instructed Moses to make sure the Israelites kept the Sabbath day holy. On the 7th day of every week, the Israelites were required not to work. This was a command for the people to have rest and remember that God provides. Christians find by the teaching of Jesus and letters in the New Testament, that the Sabbath is no longer a requirement, but many Jews and some cults still practice the Sabbath.

Jewish answer:

The Jewish Sabbath is from Friday sundown until Saturday after twilight. Its origin is in the Torah (Genesis ch.2; Exodus ch.16, ch. 20, ch.23, ch.31, ch.34, and ch.35; Leviticus ch.23 and ch.26, and other passages).

The Sabbath is considered in the Jewish religion to be a day blessed by God (Genesis ch.2), a day of rest (Exodus ch.20, ch.31), and a day of strengthening ties with the family, the community, and with God.

There are two main aspects to Shabbat observance: what we do and what we don't do.

What we don't do: we're not permitted to work on the Shabbat (Exodus ch.20). This includes 39 categories of productive interaction with the world, such as planting, writing, kindling fire, etc. (Talmud, Shabbat 73b).