ischys (ἰσχύς)

Strong’s: G2479 Part of speech: Noun, feminine, 3rd declension Glosses: strength, might, power, force

Semantic range

ἰσχύς denotes inherent strength — the raw capacity or force that a person or being possesses. It is narrower than δύναμις (dynamis), which covers ability, miracle, and army. ἰσχύς is the brute-force end of the Greek power vocabulary: strength as such.

1. Physical strength — bodily might, the power of muscle and sinew.
2. Personal might — the strength of character or will that enables action.
3. Divine might — God’s own strength, the infinite version of what human strength approximates.

The word occurs only 10 times in the NT but carries outsized theological weight because of its placement in key passages (Mark 12:30; Ephesians 1:19; 6:10; 2 Thessalonians 1:9; 1 Peter 4:11; 2 Peter 2:11; Revelation 5:12; 7:12).

Key occurrences

• Mark 12:30 / Luke 10:27 — “Love the Lord your God with all your heart, soul, mind, and ἰσχύς (strength).” Quoting Deuteronomy 6:5, where the Hebrew is מְאֹד (meod, “muchness, exceedingly”). The LXX and NT use ἰσχύς to render this — love God with the totality of your strength/force.
• Ephesians 1:19 — “the immeasurable greatness of his δύναμις… according to the ἐνέργεια τοῦ κράτους τῆς ἰσχύος αὐτοῦ — the working of the might of his strength.” Four power-words stacked: δύναμις, ἐνέργεια, κράτος, ἰσχύς. ἰσχύς is the foundation of the stack — God’s raw, inherent strength.
• Ephesians 6:10 — “Be strong in the Lord and in the κράτος τῆς ἰσχύος αὐτοῦ — the might of HIS strength.” The believer’s empowerment for spiritual warfare comes from God’s own ἰσχύς. This is the NT restatement of Judges 6:12: “The LORD is with you, mighty one in strength (δυνατὲ τῇ ἰσχύι, LXX).”
• Revelation 5:12 — “Worthy is the Lamb to receive δύναμιν καὶ… ἰσχύν — power and… strength.” Both words appear in the sevenfold ascription to Christ.
• Revelation 7:12 — The same pairing in angelic worship: “blessing and glory and wisdom and thanksgiving and honor and δύναμις and ἰσχύς to our God.”

LXX background

ἰσχύς translates primarily:

• חַיִל (chayil, H2428) — in its “strength/valor” sense (including Judges 6:12)
• כֹּחַ (koach, H3581) — “power, strength”
• עֹז (oz, H5797) — “strength, might”
• גְּבוּרָה (gevurah, H1369) — occasionally

The choice of ἰσχύς for chayil in Judges 6:12 (δυνατὲ τῇ ἰσχύι) is significant: the LXX translators selected the word for raw, inherent strength to render chayil (valor/capability). This means the angel’s greeting becomes, in Greek, “O mighty one characterized by strength” — and when Paul echoes this in Ephesians 6:10 with the same word ἰσχύς, the allusion is lexically exact.

Related words

• ἰσχυρός (ischyros, G2478) — adjective, “strong, mighty, powerful” — used of persons, winds, angels, and God
• ἰσχύω (ischyo, G2480) — verb, “to be strong, to be able, to prevail” — Philippians 4:13 uses the related ἐνισχύω/ἐνδυναμόω
• κατισχύω (katischyo, G2729) — verb, “to overpower, to prevail against” — Matthew 16:18: “the gates of Hades shall not prevail (κατισχύσουσιν) against it”
• δύναμις (dynamis, G1411) — “power, might” — see companion study; broader than ἰσχύς
• κράτος (kratos, G2904) — “dominion, ruling might” — often paired with ἰσχύς (Ephesians 1:19; 6:10)
• ἐξουσία (exousia, G1849) — “authority” — the right to exercise power, distinct from the power itself

Sources consulted

• BDAG, s.v. ἰσχύς
• Louw-Nida, domain 76.3
• NIDNTTE, s.v. ἰσχύς
• Hatch-Redpath, for LXX equivalents