A weekly rest is very important to Yahweh God. God’s Law is for our benefit and good health. The Sabbath was observed by Yahweh God Himself at the end of the Genesis chapter one creation event. So the Sabbath was not a new or added Law at the time of Moses. The Sabbath will be observed on the new earth in the next age. The Sabbath most are familiar with today is not the Sabbath of Scripture.
Here is a brief look at the Sabbath over the years of scripture. Reading the article will help explain what Pharaoh said in Exodus 5:5.
Pharaoh said, “Behold, the people of the land are now many, and you make them rest from their burdens.”