Greek word · G4456

πωρόω

pōroō

to harden

From πῶρος, a callus, a hard stony growth, or the hard tissue that forms over a broken bone. The verb means to petrify or harden, and so to make numb, insensitive, unable to feel or perceive. In NT use it is almost always cognitive: dull, obtuse, unable to take in.

Appears 5 times in 5 verses of the Greek New Testament. · Updated October 30, 2026

What it means

πωρόω, -ῶ

(πῶρος, 1. a stone. 2. a callus) [in LXX: Job 17:7 B(כָּהָה), Proverbs 10:20 A * ;]

to petrify, harden, form a callus. Metaphorical, π. τ. καρδίαν, John 12:40. Pass., Romans 11:7; τ. νοήματα, 2 Corinthians 3:14; ἡ καρδία, Mark 6:52 8:17 †

(AS)

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), via STEPBible.org (CC BY 4.0).

In depth

From the study of John 12:40

Range of meaning: From πῶρος, a callus, a hard stony growth, or the hard tissue that forms over a broken bone. The verb means to petrify or harden, and so to make numb, insensitive, unable to feel or perceive. In NT use it is almost always cognitive: dull, obtuse, unable to take in.
Against the English: Modern English "hard-hearted" means cold, cruel or unkind. The Greek picture is a heart that has gone numb like callused skin. It no longer registers what it meets. The problem is perception, not lack of compassion.
How it drifted: In modern English "heart" became the seat of emotion, so "hardened heart" came to mean emotional coldness. Ancient readers placed thinking in the heart, so a hardened heart meant a dull mind and a stubborn will.
Used elsewhere in the period: Mark 6:52 ("they had not understood about the loaves; their hearts were hardened"); Mark 8:17 ("Do you not yet perceive or understand? Are your hearts hardened?"); Rom 11:7 (Israel "was hardened"); 2 Cor 3:14 ("their minds were hardened"). Medical writers use the word family for callus formation. Several manuscripts of John 12:40 read the similar πηρόω, "to maim, disable" (see variants).

From the study of Romans 11:7

Range of meaning: From πῶρος (pōros), a porous stone (tufa) and, in medical writers, a callus: the hard tissue that forms over a healed bone fracture or on skin. The verb means to petrify, to callus over, and so, used figuratively, to make insensitive, dull or obtuse. In the NT it nearly always concerns the mind or perception: the disciples' 'hearts were hardened' so they did not understand the loaves (Mark 6:52; 8:17); 'their minds (noēmata) were hardened' (2 Cor 3:14); John 12:40 quotes Isaiah 6:10 with this verb. The noun form pōrōsis appears at Rom 11:25 ('a partial hardening has come upon Israel') and Eph 4:18.
Against the English: 'Hardened' is accurate, but modern English 'hard-hearted' suggests cruelty or emotional coldness, and 'hardened criminal' suggests a stubborn will. Paul means numbed perception: a failure to see and hear what is in front of you, as v. 8 spells out ('eyes that could not see, ears that could not hear'). The KJV's 'blinded' follows the Latin Vulgate (excaecati sunt). It catches the perception side, but it loses the image of a callus forming.
How it drifted: Ancient readers often confused or merged πωρόω (to callus) with πηρόω (to maim, disable, especially to blind), and manuscripts elsewhere swap the two (e.g. Mark 3:5; John 12:40). J. Armitage Robinson showed that early interpreters often took pōrōsis to mean blindness. Latin translators therefore chose 'blinded', and the KJV inherited it. Later, 'hardened' became tied in popular thought to the Pharaoh story, which uses a different Greek verb (sklērynō, 9:18).
Used elsewhere in the period: LXX Job 17:7: 'my eyes are dimmed (pepōrōntai) by grief', where the verb describes failing eyesight. Hippocratic and other medical writers use pōros/pōroō for bone callus. The idea of God dulling the people's perception as a judgment comes from Isaiah 6:9–10, Isaiah 29:10 and Deuteronomy 29:4, which Paul blends in v. 8.

From the study of 2 Corinthians 3:14

Range of meaning: The verb comes from πῶρος (pōros), which meant a kind of porous stone (tufa) and, in medical writers, a callus or a hard stone formed in the body. So πωρόω means 'to petrify, to form a callus, to harden'. Used of the mind it means 'to make dull, insensitive, unable to perceive'. BDAG gives 'harden, petrify', and in figurative use 'make dull/obtuse/blind'.
Against the English: Most modern versions have 'hardened' (ESV, NASB, WEB, YLT). The NIV has 'made dull', the BSB 'closed', and the KJV 'blinded'. 'Hardened' keeps the physical picture of tissue gone stiff and unfeeling. 'Blinded' turns it into a sight metaphor and runs it together with 4:4, where Paul uses a different verb (τυφλόω, 'to blind').
How it drifted: The KJV's 'blinded' comes from Tyndale. It has some ancient support: the Greek Old Testament uses the verb for eyes growing dim (Job 17:7), and copyists sometimes confused it with πηρόω, 'to maim, to blind'. But the core picture is hardening, not losing sight.
Used elsewhere in the period: Greek medical writers use πῶρος and πωρόω for the callus that forms over a broken bone. Greek OT: Job 17:7, of eyes dimmed. NT: Mark 6:52 and 8:17 (the disciples' hearts hardened), John 12:40 (quoting Isa 6:10), Rom 11:7 ('the rest were hardened'). The noun πώρωσις appears in Mark 3:5, Rom 11:25 and Eph 4:18.

Where it appears

Mark · 2

Mark 6:52 πεπωρωμένη.¶ hardened.

for they had not understood about the loaves, but their hearts had been hardened.

Here: From pōros, a callus or a lump of stone. Their inner perception had grown a callus and become numb, so it could not register what was in front of it. The form is passive and does not say who did the hardening. It describes a state already in place.
Mark 8:17 πεπωρωμένην Hardened

Aware of their conversation, Jesus asked them, “Why are you debating about having no bread? Do you still not see or understand? Do you have such hard hearts?

Here: 'Calloused, hardened.' The form describes a settled state, not a passing mood. It stands first in the clause for emphasis, and the picture is a mind that has lost its sensitivity.

John · 1

John 12:40 ἐπώρωσεν has hardened

“He has blinded their eyes and hardened their hearts, so that they cannot see with their eyes, and understand with their hearts, and turn, and I would heal them.”

Here: Aorist (simple past): "he hardened". The word pictures a callus or stony growth that makes something numb and insensitive. Here it means the heart has lost its ability to perceive and understand, not that it has become cruel.

Romans · 1

Romans 11:7 ἐπωρώθησαν were hardened

What then? What Israel was seeking, it failed to obtain, but the elect did. The others were hardened,

Here: Aorist passive, 'were made callous/insensitive'. The passive leaves the agent unnamed, but v. 8 makes it plain: 'God gave them a spirit of stupor.' The picture is dulled perception, not emotional coldness.

2 Corinthians · 1

2 Corinthians 3:14 ἐπωρώθη were hardened

But their minds were closed. For to this day the same veil remains at the reading of the old covenant. It has not been lifted, because only in Christ can it be removed.

Here: 'Were hardened', in the past tense: their minds became stiff and unfeeling, like scar tissue or stone. The passive form leaves the one doing the hardening unnamed. Elsewhere Paul attributes Israel's hardening to God (Rom 11:7–8).

Word data: STEPBible.org (CC BY 4.0), main text only.