Matthew 24:39 Commentary: Did Not Know Until the Flood

Matthew 24 sits within Jesus' Olivet Discourse, prompted by the disciples' question about the destruction of the temple and the end of the age (Matthew 24:3). The entire chapter weaves together near-term judgment on Jerusalem (fulfilled in AD 70) and the final, cosmic coming of the Son of Man. Verse 39 anchors the latter in the primeval story of Noah from Genesis 6, 8. In that account, God saw humanity's wickedness and determined to destroy the world by flood. Noah built an ark over decades, preaching righteousness (2 Peter 2:5). Yet none outside his family heeded the warning.

First-century Jewish readers would have known the flood narrative intimately. The rabbinic tradition (e.g., Mishnah Sanhedrin 11.3, cited by Gill) held that 'the generation of the flood have no part in the world to come,' underlining that their sin and disbelief were willful. In the Greco-Roman world, the idea of a cosmic deluge was not foreign, parallel flood myths circulated, but only the biblical account attaches moral and judicial weight to the event.

Jesus uses this familiar story to make a point about ignorance and readiness. The people ate, drank, married, ordinary, permissible activities, but did so without any sense of impending accountability. Their busyness was not evil in itself; it was the lack of spiritual awareness that proved fatal. The 'coming of the Son of Man' (παρουσία, meaning 'presence' or 'arrival') will likewise interrupt a world going about its normal business. The historical context of Noah's generation, then, serves as a timeless warning: divine judgment does not announce its day and hour in advance.

The supplied commentaries and lexical sources note no significant textual variants for Matthew 24:39. The Greek text is stable across the major manuscript families, with only minor differences in word order (e.g., the position of καί 'also') that do not affect meaning.

Throughout church history, Matthew 24:39 has been used to warn against spiritual complacency and to encourage readiness for Christ's return. Early church fathers like Augustine cited the flood narrative to illustrate the suddenness of final judgment. Medieval preachers often paired this verse with the Noah story to call for repentance. During the Reformation, Calvin and others emphasized that the people's ignorance was culpable, they rejected the warning Noah gave. In more recent centuries, this verse has been a staple of evangelical sermons on the second coming, often linked with Luke 17:26-27. It also appears in hymns and gospel songs that contrast the safety of the ark with the judgment of the flood. Across traditions, the verse has consistently been read as a call to watchfulness, though interpretations of the 'coming' have varied between a focus on the destruction of Jerusalem and on the final, universal judgment.

Three-point outline

1. The nature of their ignorance, They had warning (Noah's preaching, the ark's construction) but refused to believe until the flood was upon them. Their 'not knowing' was willful blindness, not lack of information.
2. The suddenness of judgment, The flood came without further notice, sweeping away all who were not in the ark. The aorist verb ἦρεν ('took away') underscores the completeness and finality of the removal.
3. The application to Christ's coming, As in Noah's day, the Son of Man will return when many are absorbed in everyday life. Jesus calls for watchfulness, not because we can calculate the date, but because we must live ready.

Five-point outline

1. Jesus compares two eras: Noah's world and the future coming of the Son of Man (v. 37).
2. Normal life continued until the day Noah entered the ark (v. 38).
3. They 'did not know' until the flood came and removed them (v. 39a).
4. The same will happen at the coming of the Son of Man (v. 39b).
5. Therefore, watch and be ready (vv. 42, 44).

Illustration hooks

• A person who ignores a hurricane warning because the weather is fine today. When the storm hits, they are caught unprepared, not because the forecast was hidden, but because they did not take it seriously.
• A student who puts off studying for a final exam, confident that there is plenty of time, until the exam day arrives and they realize they cannot cram enough.
• An office worker who dismisses repeated notices about a building evacuation drill, only to be trapped when a real emergency occurs.

Questions your congregation is asking

• How can I stay alert for Christ's return when life is so busy and nothing seems to be changing?
• Does Jesus' warning mean we should stop doing normal activities like eating, marrying, and working?
• How do I know if I am truly ready, or just assuming I am like the people in Noah's day?

This verse confronts us with a sobering truth: it is possible to hear a warning and yet not truly know it, to remain oblivious until it is too late. Jesus uses the flood story to show that His return will be sudden and final. As we discuss these questions, consider the difference between being informed and being responsive.

Discussion questions

1. Read Matthew 24:37-39. What does the comparison between Noah's day and the coming of the Son of Man teach about the timing of judgment?
2. The Greek verb for 'knew' (ἔγνωσαν) is aorist, an action that could have happened but did not. In what sense did the people 'not know'? Was it ignorance of facts, or something deeper?
3. How did Noah's generation have opportunity to know, according to the context (the building of the ark and Noah's preaching)?
4. Jesus mentions normal activities like eating and marrying. Why are these not wrong in themselves? What made them spiritually dangerous in that context?
5. How does this passage challenge the way we balance daily responsibilities with readiness for Christ's return?
6. Calvin wrote that 'unbelief had blinded their minds.' Where do you see spiritual blindness in our culture today, and how can we guard against it?
7. What is one practical step you can take this week to live with greater awareness of Christ's coming without becoming fearful or unbalanced?