The Sabbath was instituted at Creation for all mankind. It was not only for the Jewish people:
Thus the heavens and the earth were finished, and all the host of them.
Genesis 2:1-3
And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made.
And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
The Sabbath is one of the Ten Commandments:
Remember the sabbath day, to keep it holy.
Exodus 20:8-11
Six days shalt thou labour, and do all thy work:
But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work, thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor thy stranger that is within thy gates:
For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.