7 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.’”

12 Take care, brothers, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God. 13 But exhort one another every day, as long as it is called “today,” that none of you may be hardened by the deceitfulness of sin. 14 For we have come to share in Christ, if indeed we hold our original confidence firm to the end.

(ESV)