σκληρ-ύνω G4645
To harden or make obstinate; in the passive/middle, to become hardened, especially of the heart's resistance to God.
Skleruno draws on the physical image of something becoming rigid and unyielding, then transfers it to the spiritual realm. The Epistle to the Hebrews quotes Psalm 95 three times — 'Do not harden your hearts' (Heb 3:8, 3:15, 4:7) — turning the verb into a recurring pastoral alarm. Paul invokes God's sovereign prerogative: 'He hardens whom he wills' (Rom 9:18). In the passive, the word describes the tragic slide into obstinacy, as when some in Ephesus were being hardened against Paul's teaching (Acts 19:9). Spanish 'endurecer,' French 'endurcir,' and German 'verhaerten' all mirror the concrete-to-metaphorical arc.
Senses
1. harden, make obstinate (active) — To harden or make obstinate in the active sense — the deliberate act of causing a heart to become unyielding toward God's voice or truth. In Heb 3:8, 3:15, and 4:7, it appears as a subjunctive warning drawn from Psalm 95: 'Do not harden your hearts as in the rebellion.' Rom 9:18 attributes the hardening to divine agency. Multilingual glosses — Spanish 'endurezcais,' French 'endurcir,' German 'verhaerten' — consistently preserve the metaphor of making something physically rigid applied to spiritual receptivity. 4×
AR["تُقَسِّوا", "يُقَسِّي"]·ben["কঠিন-কর", "তিনি-কঠিন-করেন"]·DE["verhaerten"]·EN["harden", "he-hardens"]·FR["endurci", "endurcir"]·heb["מַקְשֶׁה", "תַּקְשׁוּ"]·HI["कठोर-करता-है", "कठोर-करो"]·ID["Ia-keraskan", "keraskan"]·IT["indurire", "sklērunēte"]·jav["Panjenenganipun-ngatosaken.", "atos-kaken"]·KO["강팩케-하지-말라", "완악하게-하시니"]·PT["endurece.", "endureçais"]·RU["ожесточает", "ожесточите"]·ES["endurece", "endurezcais"]·SW["anafanya-moyo-kuwa-mgumu", "fanyie-ugumu"]·TR["katılaştırıyor", "sertleştirmeyin"]·urd["سخت-کرتا-ہے۔", "سخت-کرو"]
2. become hardened (passive/middle) — To become hardened or grow obstinate, used in the passive or middle voice to describe the resultant state of spiritual rigidity. In Acts 19:9, the imperfect tense (esklerunonto) captures an ongoing process: some were progressively hardening themselves against the Way. Heb 3:13 warns against being hardened by sin's deceitfulness — here the passive voice suggests hardening as something that overtakes a person through neglect rather than deliberate choice, a subtle but important distinction from the active sense. 2×
AR["تَقَسَّوْا", "يَتَقَسَّى"]·ben["কঠিন-হয়", "কঠিন-হলেন"]·DE["verhaerten", "ἐσκληρύνοντο"]·EN["be-hardened", "were-being-hardened"]·FR["endurci", "endurcir"]·heb["הִתְקַשּׁוּ", "יִתְקַשֶׁה"]·HI["कठोर-हो-गए", "कठोर-हो-जाए"]·ID["dikeraskan", "menjadi-keras"]·IT["indurire", "sklērunthē"]·jav["kadadosaken-atos", "katos"]·KO["강팩케-되지", "굳어져"]·PT["se-endureciam", "seja-endurecido"]·RU["ожесточались", "ожесточился"]·ES["se-endurecían", "sea-endurecido"]·SW["fanyiwe-ugumu", "walishupaa"]·TR["katılaşıyorlardı", "sertleşsin"]·urd["سخت-ہو-جائے", "سخت-ہوتے-تھے"]
Related Senses
H3808 1. simple negation (not) (4839×)G1722 1. locative: in, within (2442×)H1004b 1. house, dwelling, building (2015×)G3756 1. not (negation particle) (1635×)H4480a 1. source or separation (1198×)H5892b 1. city, town (1093×)G1519 1. direction: into, to, toward (1061×)H3427 1. Qal: to dwell, inhabit (937×)G1537 1. from, out of (source/origin) (886×)H8034 1. Name (designation / identifier) (856×)G3361 1. subjective negation (not) (834×)G1909 1. on, upon (spatial surface) (757×)H0369 1. existential negation: there is not (738×)H5869a 1. in the eyes/sight of (evaluative) (734×)H5650 1. Servant, attendant, subject (723×)H0408 1. prohibitive negation do-not (712×)G2443 1. so that, in order that (purpose/result) (665×)G0575 1. from (649×)G1223 1. through, by means of (582×)H3541 1. thus, so, in this manner (569×)
BDB / Lexicon Reference
σκληρ-ύνω, harden, opposed to μαλάσσω, Refs 5th c.BC+:—passive, with perfect ἐσκλήρυσμαι Refs 5th c.BC+, to be hardened, grow hard, Refs 4th c.BC+ __2 metaphorically, σ. τὴν καρδίαν τινός harden his heart, LXX+NT:—passive, LXX