prevailing might: strength as it actually wins out and shows itself in force
TranslatabilityApproximateCertaintySettled
This is the side of the word that names raw, effective power. Among the New Testament's words for power it sits close to sheer strength, but with a particular shade: not the bare ability to do something, and not muscle held in reserve, but might that prevails, that carries the day and is seen doing so. It is power proven in action rather than power merely possessed.
That is why the word can name closely related things at once.
It can be the attribute itself, the overwhelming strength that belongs to God.
It can be a single mighty deed, one concrete display of that strength.
And in a fixed expression it becomes an adverb, describing something that advances by sheer force, the way an army takes a city by storm.
The writers who pile this word into long strings of power-words (in Ephesians and Colossians) are leaning on this prevailing, effective sense. In those settings the stacked terms work together as worshipful emphasis more than as a tidy ladder of distinct ideas, so the force of the whole phrase is simply: God's strength is overwhelming and it gets things done.
Nuances
1aoverwhelming strength as an attribute, the prevailing might that belongs to God
Eph 1:19Eph 6:10Col 1:11
1ba mighty deed, one concrete display of that strength
Luk 1:51*
1cby sheer force, mightily: the word used as an adverb of advance, as an army takes a city by storm
Act 19:20*
2
dominion: sovereign rule held and exercised, the right and power to reign
TranslatabilityApproximateCertaintySettled
From might that prevails it is a short step to settled rule, and this is the word's other major sense: dominion, the sovereign power to reign. This is the meaning that dominates the great praise-formulas of the New Testament, where dominion is ascribed to God and to Christ forever.
The word carried real political weight in the wider Greek-speaking world. It was the ordinary term for imperial power, the kind of rule a Caesar claimed. Many scholars hold that the biblical writers chose it deliberately: to say that dominion belongs to God and the Lamb forever is to make a counter-claim against every earthly ruler who claimed it for himself. The novelty is not the word but the one to whom it is finally assigned.
The sense has a darker edge in one place. In Hebrews the devil is said to hold the dominion of death, the only spot in the New Testament where this kind of ruling power is credited to anyone other than God or Christ. There it is a real but tyrannical grip, one that works through the fear of death, and Christ's own death breaks it. That usurped dominion is exactly what the praise-formulas then deny to anyone but God.
Nuances
2aeverlasting dominion ascribed in worship to God and to Christ
1Ti 6:161Pe 4:11*1Pe 5:11Jud 1:25Rev 1:6Rev 5:13*
2btyrannical dominion held over something: the devil's grip of death, which Christ breaks
narrows power to the kind that prevails and shows itself, not bare ability or potentialEph 1:19
Both
both name effective strength at workCol 1:11
Only power
the plain English word is broad and covers ability, permission, and influence alike, so it loses the specific note of might winning out
“might”
Comparison data is not available for this English gloss yet.
How kratos differs from similar Greek words
δύναμιςpower as inherent capacity or ability, the potential to act and to work wonders; this word instead names that strength actually prevailing and on display
Names dominion, the exercised might of one who rules, especially in doxologies ascribing everlasting power to God.1Ti 6:161Pe 5:11Jud 1:25Rev 1:6
Used of the decisive grip of overcoming power, including the power of death held by the devil and broken by Christ.Heb 2:14Luk 1:51
Both
Both name God's overwhelming strength acting on behalf of his people, and the two stand side by side describing the same mighty working.Eph 1:19Col 1:11
Names the capacity to act, the inherent ability or energy that produces an effect, often shown in concrete works of power (miracles, mighty deeds).Mat 7:22Mrk 6:5Act 1:8
Can be possessed and given to people, so it is poured out on disciples and at work within believers.Luk 24:49Act 6:8
ἰσχύςstrength as a possessed endowment, the reserve of force a person or God has; this word is that strength breaking through and winning out
Names power as exercised dominion: might that grips, holds, and prevails, often the standing rule that belongs to God forever. It is the strength of one who is in control, not merely strong.1Pe 5:11Jud 1:25
Belongs to the language of sovereignty and acclamation: the dominion ascribed to God and to the exalted Christ, and the power by which death itself is held and then broken.Rev 1:6Heb 2:14
Used of force that visibly takes effect and wins out, as when the message spreads and grows mighty and prevails. The accent is on power proving itself in action.Act 19:20Luk 1:51
Both
Both name a kind of might, and the two are heaped together to describe God's overwhelming power, so closely that English often renders them with the same family of words.Eph 1:19
Both describe the strength a believer is told to draw on from God, stacked side by side in the call to be strong in the Lord and in the might of his power.Eph 6:10
Names inherent strength: the raw capacity for force that a person or thing possesses, the muscle behind an effort. It is the word used when the command is to love God with everything one has, set beside heart, soul, and mind as a faculty to be poured out.Mrk 12:30Luk 10:27
Measures the sheer magnitude of strength a being holds, including the strength of angels weighed against one another. It rates how strong someone is, rather than the rule they exercise.2Pe 2:11Rev 5:12
ἐξουσίαauthority as a granted right, the lawful warrant to act; this word is the might that backs rule rather than the legal permission for it
Names raw might actually exerted, the strength that visibly accomplishes something, as when a strong arm scatters or a word prevails.Luk 1:51Act 19:20Eph 1:19
Belongs to the language of praise, ascribed to God in doxologies as the dominion that is forever His.1Ti 6:161Pe 4:11Rev 1:6
Both
Both can name the dominion that belongs to God, joined together when worship ascribes to Him every kind of supremacy at once.Jud 1:25
Names a granted RIGHT or warrant to act, conferred by a higher source and able to be given, withheld, or refused.Jhn 1:12Jhn 10:18Act 8:19
Marks a sphere of jurisdiction or office, the legitimate region in which someone has standing to command, such as a ruler's or court's domain.Luk 23:7Rom 13:1Mat 21:23
Used in the plural for ranks of created spiritual powers, the invisible offices and rulers in the unseen order.Eph 6:12Col 1:161Pe 3:22
This is the word worshipers put into praise, ascribing dominion to God without end: glory and dominion be his forever (1 Peter 4:11,1 Peter 5:11), honor and everlasting dominion to the only immortal God (1 Timothy 6:16), dominion to the one on the throne and to the Lamb (Revelation 5:13).1Pe 4:111Ti 6:16Rev 5:13Jud 1:25Rev 1:61Pe 5:11
Names power as a hold or mastery that someone possesses, and therefore something that can be taken away: the devil held the mastery of death until Christ's own death broke him (Hebrews 2:14).Heb 2:14
Measures sheer overpowering force: God did a mighty deed with his arm and scattered the proud (Luke 1:51), and the Lord's message kept spreading and prevailing by main force (Acts 19:20).Luk 1:51Act 19:20
Both
Both name the immense power God brought to bear in raising and enthroning Christ, and Ephesians 1:19 piles them into one phrase, the working of the might of his strength.Eph 1:19
Both stand behind God strengthening his people for hard work: Paul struggles by the working that operates in him (Colossians 1:29), while the same Colossian believers are made strong to endure in step with God's glorious might (Colossians 1:11), which is where they are told to draw their strength (Ephesians 6:10).Col 1:29Col 1:11Eph 6:10
Neither word belongs to God alone; each can be said of a hostile power, so the reader has to notice whose power is in view: Satan's working produces the lawless one's false signs (2 Thessalonians 2:9), and the devil's mastery held death itself (Hebrews 2:14).2Th 2:9Heb 2:14
Names power in the act of operating, and the text almost always says what it produces: God raising Christ out of death (Colossians 2:12), the remaking of our lowly bodies to match his glorious one (Philippians 3:21), a whole body knit together and growing (Ephesians 4:16).Col 2:12Php 3:21Eph 4:16
Describes power at work inside a person: Paul labors because God's working is working in him (Colossians 1:29), and the same working handed him the gift that made him a servant of the gospel (Ephesians 3:7).Col 1:29Eph 3:7
Can name an operation whose product is deception: counterfeit signs and lying wonders driven by Satan (2 Thessalonians 2:9), and a working of delusion sent on people who will not have the truth (2 Thessalonians 2:11).2Th 2:92Th 2:11
Names the might itself, the thing held or exercised, rather than the one who holds it, so it can be the object of a verb: God "performed" might with his arm, and his strength was at work in raising Christ.Luk 1:51Eph 1:19
Because it names a possession and not a person, it can belong to someone other than God: the devil is said to have held the "power" of death until Christ broke it.Heb 2:14
It can describe sheer force at work in something impersonal, as when Luke says the word of the Lord kept growing and prevailing "mightily" in Ephesus.Act 19:20
It is the strength a believer draws on, borrowed rather than owned: Christians are told to be strong in the Lord's might and are strengthened according to it.Eph 6:10Col 1:11
In worship it is one item among several ascribed to God, listed beside glory, honor, and majesty rather than standing on its own.Jud 1:25Rev 5:13
Both
Both point to unrivaled strength that finally belongs to God alone, whether stated as what is his forever or as the name he goes by.1Ti 6:16Rev 1:8
Both are at home in worship, and Revelation uses each in its songs of praise around the throne.Rev 1:6Rev 15:3
Both carry the note of rule and not only of raw force, which is why one is often rendered "dominion" and the other describes the God who reigns.1Pe 5:11Rev 19:6
Is a title for a person, not a quality: it names God himself and belongs to the fixed address "Lord God Almighty".Rev 4:82Co 6:18
The "all" built into the word makes the claim total: God holds and exercises rule over everything without exception, and he reigns.Rev 19:6Rev 11:17
It can stand in place of a name, so a phrase like "the great day of God the Almighty" identifies who acts without saying anything more about him.Rev 16:14Rev 19:15
It is only ever said of God, so it never describes an enemy, a creature, or a gift handed to believers.Rev 16:7Rev 21:22
kratos in the other biblical languages
עֹזHebrew“strength”the main Hebrew strength-word this term renders in the Greek Old Testament, naming might as a refuge and a possession; the Greek leans more toward might that prevails and rules
Leans toward dominion: the settled mastery or rule that someone holds, not merely the force they put forth. It is the word for the everlasting sovereignty ascribed to God in the closing praise of letters and visions.1Ti 6:161Pe 5:11Jud 1:25Rev 1:6
Names a controlling grip held over something, so that one can speak of the power of death held by the devil and broken by Christ, an idea of mastery the Hebrew word for strength never carries.Heb 2:14
Both
Both name God's overwhelming might exerted on behalf of his people, the strength by which he prevails over his enemies and rescues the weak.Luk 1:51Psa 89:10
Both are lifted up in worship as the might that belongs to God, ascribed back to him in praise as something he alone possesses forever.Rev 5:13Psa 68:34
Shades into refuge: because this strength is what keeps a person safe, the word becomes a strong place to run to, the LORD himself named as the believer's stronghold and shelter.Psa 28:8Psa 46:1Pro 18:10
Is freely used of human and created might, the force of a person's arm, a fortified tower, or a boastful nation about to be shattered, where the Greek word stays almost entirely with divine and cosmic power.Jdg 9:51Pro 31:17Ezk 30:18
Keeps company with words for splendor and majesty, so strength here can shade into the glory that strength commands, a dignity God wears and his worshipers ascribe back to him.Psa 96:6Psa 29:1
What scholars say about kratos
Foerster (TDNT 3.905-915) is the lexical anchor: kratos denotes the presence and significance of force as prevailing might, more akin to ischys than to dynamis, and by extension dominion. BDAG (565) gives three senses: power/might as inherent attribute (Eph 1:19;Col 1:11;Heb 2:14), mighty deed (Luke 1:51, a cognate accusative of poieo), and ruling power/sovereignty (the doxologies); kata kratos at Acts 19:20 is the classical military adverbial idiom. Louw-Nida (Domain 76) and Muraoka (LXX lexicon, adding a moral-fortitude sense for 4 Maccabees) agree. The word has a long classical career (LSJ: strength, sovereignty, mastery) and became standard imperial Greek (autokrator for imperator). Foerster, followed by the standard commentators, judges NT usage to be mediated through Hellenistic-Jewish liturgical-philosophical usage (Wisdom 11:21; Sirach 18:5; Psalms of Solomon 17:3) rather than directly through Hebrew vocabulary. On the doxologies, the form-critical consensus (Deichgraeber; Bauckham, WBC Jude, 119-124) traces the form to Jewish liturgy while the function is widely read as polemical against imperial counter-claims, near-universally for Revelation (Aune; Beale; Bauckham, Theology of the Book of Revelation) and well-attested for 1 Peter (Elliott; Achtemeier) and the Pastorals (Marshall; Towner). Hebrews 2:14 (the devil holding the dominion of death) follows the classical idiom for holding dominion over something and grounds patristic Christus Victor soteriology (Attridge; Lane; Cockerill). Hurtado treats the sharing of kratos with the Lamb at Revelation 5:13 as strong evidence for the earliest worship of Jesus.
Where scholars disagree about kratos
Whether the stacked power-words in the genitive chains of Ephesians and Colossians carry distinct lexical meanings or function together as worshipful emphasis.
contestedThe terms keep meaningful distinctions even when stacked, so kratos retains its specific sense of prevailing, dominion-aspect might within the chain.; H. Hoehner, Ephesians, 269-273; A. Lincoln, Ephesians (WBC 42), 60-61
contestedIn these Semitic-style cascades the terms function cumulatively as liturgical intensification, not as a clean taxonomy.; E. Best, Ephesians (ICC), 165-167; P. O'Brien, Colossians, Philemon (WBC 44), 24-25
In-depth research
This is a research paper, so it may be hard to read without scholarly background. It is useful if you want to dig even deeper into this word.
Sources
W. Foerster, "κράτος," TDNT, vol. III, 905-915theological-dictionary