HEBREWS 3:7-4:11 CONSTITUTES A sustained argument. We may briefly summarize what Hebrews 3:7-19 says and focus attention on Hebrews 4:1-11.
The author of Hebrews quotes Psalm 95:7-11 (Heb. 3:7-11), which finds the Holy Spirit (Heb. 3:7), the ultimate author of Scripture, saying, in effect, "Today do not harden your heart as your forefathers did at Kadesh Barnea, when they first approached the Promised Land. The majority of the spies gave a faithless report, with the consequence that the covenant people spent the next forty years wandering around the desert instead of entering into the rest that had been promised them. But today, do not make the same mistake. If you hear the voice of God, believe and obey---unlike the response of your forefathers." The very people whom God had saved from slavery were the ones he condemned to wander and die in the desert. So today the people of God should persevere in their faith and obedience, and not tumble into the unbelief (Heb. 3:19) of their ancestors.
So far the argument is one of analogy. Hebrews 4 takes it much farther. If God is still offering rest to people in the time of Psalm 95, it follows that the rest provided by the Promised Land was never meant to be the ultimate rest. For Joshua did lead the people into the land, yet "if Joshua had given them rest, God would not have spoken later about another day" (Heb. 4:8). Moreover, when God swears in his anger that the generation at Kadesh Barnea will never enter into "my rest" (Ps. 95:11; Heb. 3:11; 4:3), the thoughtful reader must ask what this "rest" of God really is. God first "rests" at the end of creation week (Gen. 2:2). That becomes a model for the covenantal Sabbath-rest. Yet neither the Sabbath-rest nor the rest in the Promised Land constitute the ultimate rest, for here in Psalm 95, "a long time later" (Heb. 4:7), God still invites people to enter his rest, on the condition of persevering faith (Heb. 4:2, 11).
The ultimate rest, the writer of Hebrews insists, can only be the Gospel, in which men and women cease from their works (as God rested from his at Creation). All of this argumentation depends on reading the Bible in its salvation-historical progression, that is, reading it sequentially along its story-line and observing how the bits not only hang together but point forward and anticipate greater things to come. The argument is not one of analogy but of typology. That is what is calling us to persevering faith and obedience; that is part of what makes the word of God living, active, and penetrating (Heb. 4:12-13).