Hebrews 4 is not speaking of the sabbath day. Joshua is mentioned as not giving them rest (He CANT) and he is come after the law of Moses regarding the sabbath. Therefore God is speaking of another DAY.
Another reason why this is not the sabbath, is it clearly says we who believe have entered into God's rest
Not that we enter this rest once a week.
And wrapping it up, for he who has entered His rest has himself also ceased from his works as God
did from His.
We are in a state of permanent rest with God.
Our New Covenant is a great salvation.
Hebrews 4
1 Therefore, since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it. 2 For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, [
a]not being mixed with faith in those who heard
it. 3 For we who have believed do enter that rest, as He has said:
“So I swore in My wrath,
‘They shall not enter My rest,’ ”
although the works were finished from the foundation of the world. 4 For He has spoken in a certain place of the seventh
day in this way: “And God rested on the seventh day from all His works”; 5 and again in this
place: “They shall not enter My rest.”
6 Since therefore it remains that some
must enter it, and those to whom it was first preached did not enter because of disobedience, 7 again He designates a certain day, saying in David, “Today,” after such a long time, as it has been said:
“Today, if you will hear His voice,
Do not harden your hearts.”
8 For if [
b]Joshua had given them rest, then He would not afterward have spoken of another day. 9 There remains therefore a rest for the people of God. 10 For he who has entered His rest has himself also ceased from his works as God
did from His.