Strong G4645 σκληρύνω sklērunō · to harden

Hebrews

1. Hebrews 3:8
   Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:
2. Hebrews 3:13
   But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.
3. Hebrews 3:15
   While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation.
4. Hebrews 4:7
   Again, he limiteth a certain day, saying in David, To day, after so long a time; as it is said, To day if ye will hear his voice, harden not your hearts.