Abrahamic Covenant vs Mosaic Covenant

Paul continues in his letter to the Galatians to explain the difference between grace and the law. "Abraham believed God, and it was counted unto him for righteousness." It is only through faith that a person is saved. Not by any works or any keeping of the law. Paul also deals with the issue that once a person is given salvation there is nothing that has to be added to it out of any law, Jewish or Gentile to be "really" saved.