Hebrews 4:5
And in this place again, If they shall enter into my rest.
Cross-reference
Hebrews 4:3
Contrast
Hebrews 4:3 states that believers enter God's rest, contrasting with the warning in v.5 that some will not enter.
Hebrews 3:11
Citation
In Hebrews 3:11, the same quotation from Psalm 95 appears — God's oath that the rebellious generation would not enter His rest.
Psalm 95:11
Citation
Psalm 95:11 is the source of the quote — God swore they would not enter His rest, which Hebrews applies to the promise of Sabbath rest.