For the Biblical definition of sin click here
However we read today that the son of the stranger (one whom is not from among the children of Israel) should keep the Sabbath day as well. There is only 1 Law for the Jew and the Gentile. 1 Law for Israel, as well as for the entire species of Man (the species of Man is male and female).
It is very important that we use the Word. Those that sanctify themselves without the Word are in danger.