World Wide Study Bible
a Bible passage
8 For if Joshua had given them rest, God would not speak later about another day.
8. For if Jesus had given them rest, or, had obtained rest for them, etc. He meant not to deny but that David understood by rest the land of Canaan, into which Joshua conducted the people; but he denies this to be the final rest to which the faithful aspire, and which we have also in common with the faithful of that age; for it is certain that they looked higher than to that land; nay, the land of Canaan was not otherwise so much valued except for this reason, because it was an image and a symbol of the spiritual inheritance. When, therefore, they obtained possession of it, they ought not to have rested as though they had attained to the summit of their wishes, but on the contrary to meditate on what was spiritual as by it suggested. They to whom David addressed the Psalm were in possession of that land, but they were reminded of the duty of seeking a better rest.
We then see how the land of Canaan was a rest; it was indeed but evanescent, beyond which it was the duty of the faithful to advance. In this sense the Apostle denies that that rest was given by Joshua; for the people under his guidance entered the promised land for this end, that they might with greater alacrity advance forward towards heaven.
And we may hence easily learn the difference between us and them; for though the same end is designed for both, yet they had, as added to them, external types to guide them; not so have we, nor have we indeed any need of them, for the naked truth itself is set before our eyes. Though our salvation is as yet in hope, yet as to the truth, it leads directly to heaven; nor does Christ extend his hand to us, that he may conduct us by the circuitous course of types and figures, but that he may withdraw us from the world and raise us up to heaven. Now that the Apostle separates the shadow from the substance, he did so for this reason, — because he had to do with the Jews, who were too much attached to external things.
He draws the conclusion, that there is a sabbathizing reserved for Gods people, that is, a spiritual rest; to which God daily invites us.