'Hearts' in the Bible

do not harden your hearts as in the rebellion,on the day of testing in the wilderness,

for 40 years.Therefore I was provoked with that generationand said, “They always go astray in their hearts,and they have not known My ways.”

As it is said:Today, if you hear His voice,do not harden your hearts as in the rebellion.

again, He specifies a certain day—today—speaking through David after such a long time, as previously stated:Today, if you hear His voice,do not harden your hearts.

But this is the covenantthat I will make with the house of Israelafter those days, says the Lord:I will put My laws into their mindsand write them on their hearts.I will be their God,and they will be My people.

This is the covenant I will make with themafter those days, says the Lord:I will put My laws on their heartsand write them on their minds,

let us draw near with a true heart in full assurance of faith, our hearts sprinkled clean from an evil conscience and our bodies washed in pure water.