'Do Not Harden Your Hearts' in the Bible

Do not harden your hearts as [your fathers did] in the rebellion [of Israel at Meribah],On the day of testing in the wilderness,

while it is said,“Today [while there is still opportunity] if you hear His voice,Do not harden your heart, as when they provoked Me [in the rebellion in the desert at Meribah].”

He again sets a definite day, [a new] “Today,” [providing another opportunity to enter that rest by] saying through David after so long a time, just as has been said before [in the words already quoted],“Today if you hear His voice,Do not harden your hearts.”