Hebrews 4:8-9 For if Joshua had given them rest, then He would not afterward have spoken of another day. There remains therefore a rest for the people of God.

Although Israel was delivered from Egyptian bondage, they did not get to sit down and take it easy.
It was their own fault because they fought God through pride, fear, and stubbornness.
Israel eventually entered the promise land but never entered into a rest.
Even today, they are surrounded by enemies and never rest from vigilance and hostility toward them.
Sin does not let you rest.
It is your enemy and you must constantly be vigil against it.
There remains therefore a rest for the people of God.
You cannot rest today because someone needs to hear the Gospel.
You cannot rest today because someone needs prayer.
You cannot rest today because someone needs the word explained.
Sin is not letting you rest today, not because it has rule over you, for Jesus has done away with sins power over you; but because sin still has so many in bondage.
However, the day is coming when sin is completely destroyed and you enter the rest of God.