Did the word "believe" mean something different in the Bible than it does now?

Key facts

• In pre-Christian Greek, pistis was used in military, legal and commercial contexts for trust, loyalty and good faith between people. [Morgan 2015]
• Teresa Morgan's study traces how pistis and its Latin counterpart fides functioned as relational trust in the early Roman Empire and in the early churches. [Morgan 2015]
• The standard New Testament lexicon gives trust and reliance as core senses of the pistis word group, alongside belief. [BDAG, s.v. πίστις, πιστεύω]
• Paul quotes Habakkuk 2:4 ("The righteous will live by faith", NIV) in Romans 1:17 and Galatians 3:11, and Hebrews 10:38 quotes it as well; the Hebrew has emunah (אֱמוּנָה), steadfast faithfulness, and the Greek has pistis. [Habakkuk 2:4; Romans 1:17; Galatians 3:11; Hebrews 10:38; BDB, s.v. אֱמוּנָה]
• The Latin Vulgate renders pistis as fides and pisteuō as credere, two words from different roots; John 3:16 reads omnis qui credit in eum. [Vulgate, John 3:16]
• The Vulgate renders hypostasis in Hebrews 11:1 as substantia. [Vulgate, Hebrews 11:1]
• The Greek metanoia (μετάνοια), a change of mind, was rendered in Latin by paenitentia, a word associated with penitence and penance. [Thayer, s.v. μετάνοια; The Weight of God, Ch. 5]
• English "believe" descends from Old English (ge)lȳfan, which is related to lēof, "dear, beloved", and to the modern word "love"; "faith" entered English later from Old French, from Latin fides. [Oxford English Dictionary, "believe"; Online Etymology Dictionary, "believe"]
• Because of this history, modern English uses a Latin-derived noun ("faith") and a Germanic verb ("believe") for what is one word group in Greek. [BDAG; Oxford English Dictionary, "believe", "faith"]

Key terms

pistis πίστις

trust, reliance, faithfulness; the New Testament noun translated 'faith'

pisteuō πιστεύω

to trust, rely on, believe; the verb translated 'believe'

emunah אֱמוּנָה

steadfastness, faithfulness; sustained reliance (Habakkuk 2:4)

fides (Latin)

trust, good faith, loyalty; the Latin rendering of pistis

credere (Latin)

to believe, to entrust; the usual Latin rendering of pisteuō

gelȳfan (Old English)

to believe; related to lēof, 'dear, beloved'

metanoia μετάνοια

change of mind, reorientation; translated 'repentance'

paenitentia (Latin)

penitence, penance; the Latin rendering of metanoia

Explanation

Stage 1: pistis in everyday Greek

Before the New Testament was written, pistis was an ordinary word. It appears in settings where trust carried consequences: oaths, treaties, contracts, marriages, and the loyalty of soldiers to commanders. Teresa Morgan's research documents this secular background in detail. The book summarises its common thread: someone relying on another's proven character, with real cost if that character failed. This is why the New Testament writers could use the word without explanation: their readers already knew what it meant to put their trust in someone.

Stage 2: carrying the Hebrew

The Greek also had to carry the Hebrew vocabulary of trust: aman (to be firm, reliable), batach (to trust, rely on) and emunah (steadfastness, faithfulness). Habakkuk 2:4 says the righteous live by emunah; Paul's letters and Hebrews quote that line with pistis. N. T. Wright's work on Paul treats the relationship between pistis and covenant faithfulness as central to Paul's theology. In this setting pistis is relational and sustained, not a single act of assent.

Stage 3: Latin

The Vulgate translated the noun pistis as fides, a word that in Roman culture carried weight: oath-keeping, loyalty, good faith. The verb pisteuō became credere. Latin therefore already split one Greek word group across two roots. The Weight of God argues that over the medieval centuries fides came to be associated with belonging to the institutional church and affirming its creed, so that its sense of personal reliance faded. The book makes a parallel claim about metanoia: rendered as paenitentia, repentance became tied to penance and sorrow rather than reorientation.

Stage 4: the Reformation

The book credits the Reformers with recovering salvation by grace through faith against a system of works and indulgences. Its argument is that they inherited the word "faith" already narrowed by its Latin history. They clarified what faith is not (earning, paying, performing) without restoring what pistis positively meant.

Stage 5: English

"Believe" comes from Old English, where it is related to lēof ("dear") and to "love"; the book notes that it once meant something closer to holding dear or committing to. "Faith" came into English from French. In modern usage both have weakened. "I believe it will rain" and "I believe in the resurrection" use the same verb for very different things, and "faith" is commonly understood as belief held without evidence. The book's summary of the whole movement: "What started as 'throw your full weight onto this' eventually became 'I think this might be true'."

Why the drift matters

The practical effect is on how familiar verses are heard. A modern reader of John 3:16 can take "whoever believes in him" to mean "whoever holds the opinion that Jesus is the Son of God". A first-century reader of πιστεύων εἰς αὐτόν would more naturally hear trust placed in a person. James 2:19 shows that the New Testament itself distinguishes these: the demons hold the correct opinion and are not saved. When "believe" means only "hold an opinion", that distinction becomes very hard to see.

What did not change

The drift concerns the receiving languages, not the Greek text. The New Testament still says pistis and pisteuō. The question is whether English readers hear trust and reliance when they read "faith" and "believe".

Common misunderstandings

• "The Bible's text has been changed." Correction: the drift is in the meaning of English (and earlier Latin) words used to translate the Greek, not in the Greek manuscripts.
• "'Believe' in the Bible means 'think it is probably true'." Correction: pistis and pisteuō centrally mean trust and reliance on a person. Holding something to be true is part of the range, not the whole.
• "Faith and belief are different biblical concepts." Correction: they translate the same Greek word group. The difference between them is a feature of English.
• "Repentance means feeling sorry." Correction: metanoia means a change of mind and direction. The association with sorrow and penance comes largely through Latin paenitentia.

What the book argues

The Weight of God argues that the most important word in Christianity has passed through a centuries-long game of telephone and now means almost the opposite of what it once did (Chapter 5). Its chain is: pistis (Greek) to fides (Latin) to faith (English) to believe (cultural drift) to opinion (modern usage). The secular background of pistis is documented scholarship (Morgan); the book's claims about medieval fides becoming "a membership card", and the Reformers recovering grace but not pistis, are its own historical interpretation, offered at a popular level. The book proposes "weight transfer" as its image for pistis, describing it as "my metaphor" for what the lexical sense of trust and reliance looks like in practice (Chapter 5). It argues that this drift is why saving trust and mere assent now sound identical in English (Chapter 6).

In the book: Chapter 5: The Drift; Chapter 3: Believe; Chapter 4: Childlike Faith.

Sources

1. Morgan, Teresa. Roman Faith and Christian Faith: Pistis and Fides in the Early Roman Empire and Early Churches. Oxford: Oxford University Press, 2015.
2. Wright, N. T. Paul and the Faithfulness of God. Minneapolis: Fortress Press, 2013.
3. Arndt, William F., F. Wilbur Gingrich, Frederick W. Danker and Walter Bauer. A Greek-English Lexicon of the New Testament and Other Early Christian Literature, 3rd edn (BDAG). Chicago: University of Chicago Press, 2000. Entries for πίστις, πιστεύω.
4. Thayer, Joseph Henry. Thayer's Greek-English Lexicon of the New Testament. Peabody, MA: Hendrickson, 1995 (reprint of 1886 edn).
5. Brown, Francis, S. R. Driver and Charles A. Briggs. A Hebrew and English Lexicon of the Old Testament (BDB). Oxford: Clarendon Press, 1907. Entries for אָמַן, אֱמוּנָה, בָּטַח.
6. Latin Vulgate.
7. Novum Testamentum Graece, Nestle-Aland 28th edn (NA28).
8. Oxford English Dictionary, entries "believe" and "faith".
9. Online Etymology Dictionary, entry "believe".
10. Wong, Matthew. The Weight of God: How to Believe. Australia, 2026. ISBN 978-1-7646297-3-7. Chapters 3, 4, 5 and 6.