Nay`
To the 12 Tribes of Israel alone was strict Sabath given to keep as Law.
The teachers of the World and chosen people will be therefore given highest responsibility and must adhere to the sabath that a Gentile does not by law have to follow.
Peace.
Nay? islam does not observe the true Sabbath, If they do not claim to follow the correct sabbath then they should stop calling their friday thing the Sabbath, they should call it something else and be done with it.
And yes the jews must keep the true Sabbath strictly if not they are damned to hell.
All Praise The Ancient Of Days