Hebrews 4:1; Hebrews 4:6-8
For as long, then, as that promise of resting in him pulls us on to God's goal for us, we need to be careful that we're not disqualified.
So this promise has not yet been fulfilled. Those earlier ones never did get to the place of rest because they were disobedient.
God keeps renewing the promise and setting the date as today, just as he did in David's psalm, centuries later than the original invitation: Today, please listen, don't turn a deaf ear . . .
And so this is still a live promise. It wasn't canceled at the time of Joshua; otherwise, God wouldn't keep renewing the appointment for "today."