G4645 — skleruno
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
skleruno — pronounced sklay-roo'-no
from 4642; to indurate, i.e. (figuratively) render stubborn:--harden. see GREEK for 4642
6 occurrences in the KJV.
Acts 19:9
But when divers were hardened, and believed not, but spake evil of that way before the multitude, he departed from them, and separated the disciples, disputing daily in the school of one Tyrannus.
Romans 9:18
Therefore hath he mercy on whom he will have mercy, and whom he will he hardeneth.
Hebrews 3:8
Harden not your hearts, as in the provocation, in the day of temptation in the wilderness:
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.
Hebrews 3:15
While it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation.
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.