σκληρύνω (sklērunō)
sklērunō
to harden
Quick Reference
- Language
- Koine Greek
- Testament
- New Testament
- Occurrences
- 6 verses
- Root
- —
Word Overview
The verb sklērunō means to make something hard or stiff, but in Scripture it is almost always used metaphorically for the human heart. It describes a process where a person becomes obstinate, stubborn, or resistant to truth. This usage appears frequently in the New Testament, particularly in Romans and Hebrews, often echoing the Old Testament narrative of Pharaoh’s refusal to release Israel.
Its root word, skleros, simply means "hard" or "rough," providing a vivid physical image for a spiritual condition. The sources note that it is used both actively, when God hardens a heart as in Romans 9:18, and passively, when people harden themselves against the Holy Spirit’s prompting, as seen in Hebrews 3:8 and Acts 19:9. This dual usage highlights the tension between divine sovereignty and human responsibility in biblical theology.
Translators typically render sklērunō as "harden," capturing the sense of a heart becoming like stone—unyielding and unresponsive. The term carries significant theological weight, illustrating how persistent rejection of God’s voice can lead to a state of spiritual insensitivity. It serves as a warning against the gradual hardening that occurs when conscience is repeatedly ignored.
Based on public-domain lexicons (Strong's, Thayer, Gesenius, Brown-Driver-Briggs and others).
What This Word Means for Your Faith
The word sklērunō describes a heart that has become stiff and unyielding, much like stone. In Scripture, this is rarely a sudden event but rather a gradual process. It happens when we repeatedly ignore the gentle promptings of God’s voice or allow the deceitfulness of sin to dull our spiritual sensitivity. This hardening makes us resistant to truth and difficult to reach with love.
Yet there is hope in the warning itself. The fact that Hebrews urges believers to exhort one another "day by day" shows that this condition can be prevented and reversed through community. When we stay connected to other Christians and listen for God’s voice while it is still called "today," we keep our hearts soft and responsive.
This word invites us to examine our own lives with honesty. Are there areas where we have become stubborn or closed off? The invitation is not to fear hardening, but to actively choose openness, trusting that God desires mercy over judgment and wants to restore our capacity to hear Him clearly.
How it's translated
How this word is rendered word-by-word in the 6 verses where it appears, by frequency.
- shall harden3×
- were hardened1×
- may be hardened1×
- He hardens.1×
Forms in the text
The inflected forms of this word as they appear in Scripture, by frequency.
- σκληρύνητε3×
- ἐσκληρύνοντο1×
- σκληρύνει.¶1×
- σκληρυνθῇ1×
Key Verses
-
Hebrews 3:13
but exhort one another day by day, so long as it is called “today”, lest any one of you be hardened by the deceitfulness of sin.
This verse identifies the specific danger of sin's deceitfulness as the agent that hardens hearts, emphasizing the need for daily mutual encouragement to prevent this spiritual stiffness.
-
Romans 9:18
So then, he has mercy on whom he desires, and he hardens whom he desires.
Here the term highlights the sobering reality of divine sovereignty, where God actively hardens those who have persistently rejected His mercy, illustrating the serious consequences of obstinacy.
-
Hebrews 3:8
don’t harden your hearts as in the rebellion, in the day of the trial in the wilderness,
By recalling the wilderness rebellion, this verse warns that hardening is a choice made in response to trial, urging readers not to repeat the disobedience of Israel's ancestors.