This is the improvement of the former instance, Hebrews 4:7. If Joshua, by bringing Israel into Canaan, had given rest to all believers, then God would not by David have spoken of another day and state of rest to come. Joshua was a type of Jesus bringing believers into the true rest of the heavenly Canaan, as he did Israel into a literal one, Acts 7:45. For if Jesus had given them rest; if that of Canaan was the full and perfect rest of believers, which was given them by him. Then would he not afterward have spoken of another day; then God himself would not have spoken by David of a better and heavenly rest promised believers in the gospel; of which spiritual and eternal one, both God's seventh-day sabbath, and the rest of Canaan, were but fainter shadows and types. The expostulation is vehemently denying it.
Related Commentaries of Hebrews 4:8
Hebrews 4:8
8 For if Jesusb had given them rest, then would he not afterward have spoken of another day.