Hebrews 3:8

⁶ But Christ as a son over his own house; whose house are we, if we hold fast the confidence and the rejoicing of the hope firm unto the end.

⁷ Wherefore (as the Holy Ghost saith, To day if ye will hear his voice,

Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:

⁹ When your fathers tempted me, proved me, and saw my works forty years.

¹⁰ Wherefore I was grieved with that generation, and said, They do alway err in their heart; and they have not known my ways.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: do not harden your hearts, as you did in the rebellion, in the day of testing in the wilderness,
KJV: Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:
WEB: don’t harden your hearts as in the rebellion, in the day of the trial in the wilderness,
ASV: Harden not your hearts, as in the provocation, Like as in the day of the trial in the wilderness,
DARBY: harden not your hearts, as in the provocation, in the day of temptation in the wilderness;
BLB: do not harden your⁺ hearts, as in the rebellion, in the day of testing in the wilderness,

ÅB: da forherd ikke deres hjerter som ved forbitrelsen, på fristelsesdagen i ørkenen,
OTB: så gjør ikke hjertene harde som under opprøret,
i prøvelsens tid i ørkenen,
B1930: da forherd ikke eders hjerter som ved forbitrelsen, på fristelsesdagen i ørkenen,

Proverbs 28:14
Happy is the man that feareth alway: but he that hardeneth his heart shall fall into mischief.
Read in context
Exodus 17:7
And he called the name of the place Massah, and Meribah, because of the chiding of the children of Israel, and because they tempted the LORD, saying, Is the LORD among us, or not?
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Matthew 13:15
For this people’s heart is waxed gross, and their ears are dull of hearing, and their eyes they have closed; lest at any time they should see with their eyes, and hear with their ears, and should understand with their heart, and should be converted, and I should heal them.
Read in context
Zechariah 7:11–12
But they refused to hearken, and pulled away the shoulder, and stopped their ears, that they should not hear.
Read in context
Jeremiah 7:26
Yet they hearkened not unto me, nor inclined their ear, but hardened their neck: they did worse than their fathers.
Read in context
Daniel 5:20
But when his heart was lifted up, and his mind hardened in pride, he was deposed from his kingly throne, and they took his glory from him:
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Psalms 78:56
Yet they tempted and provoked the most high God, and kept not his testimonies:
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Ezekiel 3:7–9
But the house of Israel will not hearken unto thee; for they will not hearken unto me: for all the house of Israel are impudent and hardhearted.
Read in context