A sabbath rest (sabbatismos). Late word from sabbatizō (Exo 16:30) to keep the Sabbath, apparently coined by the author (a doubtful passage in Plutarch). Here it is parallel with katapausis (cf. Rev 14:13).
For the people of God (tōi laōi tou theou). Dative case of blessed personal interest to the true Israel (Gal 6:16).