Biblical explanation
Hebrews 4 begins by discussing God's promise of entering His rest. The writer then goes back to creation: "For he spake in a certain place of the seventh day on this wise, And God did rest the seventh day from all his works." Hebrews 4:4 The chapter then says: "For if Jesus [Joshua] had given them rest, then would he not afterward have spoken of another day." Hebrews 4:8 Then comes the important statement: "There remaineth therefore a rest to the people of God." Hebrews 4:9 The Greek word used in verse 9 is related specifically to Sabbath observance. The passage therefore brings together three ideas: God's rest at creation Israel's failure to enter God's spiritual rest through unbelief A continuing rest available to God's people Verse 10 says that the person who enters God's rest "hath ceased from his own works, as God did from his." Thus Hebrews does not merely tell Christians to perform a ritual. It calls them to trust God, cease from self-reliance, and enter His rest. At the same time, the writer deliberately connects this rest with the seventh day and creation. Hebrews 4 does not say that the Sabbath was abolished. Instead, it says that a Sabbath rest "remaineth" for God's people while also expanding the concept to include spiritual rest in Christ.
Key takeaway
Salvation is entirely by grace through faith in Christ. His atoning sacrifice, heavenly ministry, and intercession are the foundation of assurance; obedience, Sabbath faithfulness, and loving service are the fruit of a redeemed life, never a way to purchase acceptance with God.