Greek word · G101

ἀδυνατέω

adynateō

not to be able

'To be unable' or 'to be impossible'. In biblical Greek it most often appears in statements about what is impossible for God, or rather what is not.

Appears 2 times in 2 verses of the Greek New Testament. · Updated October 22, 2026

What it means

ἀδυνατέω, -ῶ

(ἀδύνατος), [in LXX: Deuteronomy 17:8, Zechariah 8:6 (פּלא ni.), Job 42:2 (בּצר ni.), al. ;]

1. Abbott-Smith omits this number to be unable (cl., Philo; π., see MM, VGT, see word).

2. In LXX and NT (Kennedy, Sources, 124; Hatch, Essays, 4; Field, Notes, 46 f.), to be impossible: Matthew 17:20, Luke 1:37.

† (AS)

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

Range of meaning: 'To be unable' or 'to be impossible'. In biblical Greek it most often appears in statements about what is impossible for God, or rather what is not.
Against the English: 'Nothing will be impossible for you' is accurate. What English loses is the echo of God-language and the link with the disciples' 'we were not able' in v.19.
How it drifted: Read on its own as a motivational slogan, the line sounds like a promise of unlimited personal potential.
Used elsewhere in the period: Greek Old Testament: Genesis 18:14, 'Is anything impossible (adunatei) for God?'; Job 42:2, Job to God: 'nothing is impossible for you' (adunatei de soi outhen); Zechariah 8:6. In the New Testament: Luke 1:37, 'nothing will be impossible with God' (ouk adunatēsei para tou theou). BDAG s.v. ἀδυνατέω.

Range of meaning: Literally "to be without power (dynamis)". With a person as subject it means "to be unable". With a thing as subject, mostly in the Septuagint, it means "to be impossible, to be too hard".
Against the English: "Be impossible" can sound abstract or philosophical, as though it were about logical possibility. The Greek is about power and ability: whether something can actually be done. With "word" as subject, the BSB/NIV "fail" and the RV/ASV "be void of power" capture this.
How it drifted: Modern debates about omnipotence ("can God make a stone too heavy to lift?") make "impossible" sound like a statement about logic. The first hearers heard a statement about whether God's power would come through.
Used elsewhere in the period: Septuagint Genesis 18:14 (present tense ἀδυνατεῖ). Job 42:2 in the Septuagint: "I know that you can do all things, and nothing is impossible (adynatei) for you." Zechariah 8:6 in the Septuagint. Matthew 17:20: "nothing will be impossible for you" (ouden adynatēsei hymin). The verse is rare in the New Testament.

Matthew · 1

Matthew 17:20 ἀδυνατήσει will be impossible

“Because you have so little faith,” He answered. “For truly I tell you, if you have faith the size of a mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move. Nothing will be impossible for you.”

Here: 'Will be impossible'. It picks up the disciples' complaint 'we were not able' (ouk ēdunēthēmen, v.19) from the same root. The Greek Old Testament uses this verb for what is or is not impossible for God (Genesis 18:14; Job 42:2).

Luke · 1

Luke 1:37 ἀδυνατήσει will be impossible

For no word from God will ever fail.”

Here: Future tense: "will be powerless / will prove impossible". If the subject is a word, the sense is "fall powerless, fail to come true". If the subject is a thing, the sense is "be beyond doing". The future looks ahead to the events just promised.

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