That is why the Holy Spirit says, "Today you must listen to his voice.
Don't harden your hearts against him as Israel did when they rebelled, when they tested God's patience in the wilderness.
There your ancestors tried my patience, even though they saw my miracles for forty years.
So I was angry with them, and I said, 'Their hearts always turn away from me. They refuse to do what I tell them.'
So in my anger I made a vow: 'They will never enter my place of rest.'"
References for Hebrews 3:11
Be careful then, dear brothers and sisters. Make sure that your own hearts are not evil and unbelieving, turning you away from the living God.
References for Hebrews 3:12
You must warn each other every day, as long as it is called "today," so that none of you will be deceived by sin and hardened against God.
For if we are faithful to the end, trusting God just as firmly as when we first believed, we will share in all that belongs to Christ.
But never forget the warning: "Today you must listen to his voice. Don't harden your hearts against him as Israel did when they rebelled."
References for Hebrews 3:15
And who were those people who rebelled against God, even though they heard his voice? Weren't they the ones Moses led out of Egypt?
And who made God angry for forty years? Wasn't it the people who sinned, whose bodies fell in the wilderness?
And to whom was God speaking when he vowed that they would never enter his place of rest? He was speaking to those who disobeyed him.
So we see that they were not allowed to enter his rest because of their unbelief.