Hard hearts find no rest.

Hebrews 3:7-11 ESV  Therefore, as the Holy Spirit says, “Today, if you hear his voice,  [8]  do not harden your hearts as in the rebellion, on the day of testing in the wilderness,  [9]  where your fathers put me to the test and saw my works for forty years.  [10]  Therefore I was provoked with that generation, and said, ‘They always go astray in their heart; they have not known my ways.’  [11]  As I swore in my wrath, ‘They shall not enter my rest.’”