The anyonymous author of Hebrews found different ways of describing the superiority of the Lord Jesus Christ. One of them, which forms the underlying motif of chapters 3 and 4, is that Jesus Christ gives the rest that neither Moses nor Joshua could provide. Under Moses, the people of God were disobedient and failed to enter into God’s rest (Heb. 3:18). Psalm 95:11 (quoted in Hebrews 4:3) implies that Joshua could not have given the people “real rest” since “through David” God speaks about the rest he will give on another day (Heb. 4:7). This in turn implies that “There remains a sabbath rest for the people of God” (Heb. 4:9).

In speaking of this rest (Heb. 3:18; 4:1, 3-6, 8) the author consistently used the same word for “rest” (katapausis). Suddenly, in speaking about the “rest” that remains for the people of God, he uses a different word (sabbatismos, used only here in the NT) meaning specifically a Sabbath rest. In the context of his teaching, this refers fundamentally to the “Sabbath rest” which is found in Christ (“Come . . . I will give you rest,” Matt. 11:28-30). Thus we are to “strive to enter that rest” (Heb. 4:11). – Sinclair Ferguson, Sabbath Rest