He said, “Go, and tell this people, ‘You hear indeed, but don’t understand; and you see indeed, but don’t perceive.’ Make the heart of this people fat. Make their ears heavy, and shut their eyes; lest they see with their eyes, and hear with their ears, and understand with their heart, and turn again, and be healed.”
⛓ Read Isaiah 6 forward — the whole chapter and its afterlife →Where this passage surfaces again, sorted by the strength of the link. Each kind of reuse — formal quotation, deliberate allusion, faint echo, figural pattern — carries its own mark. Follow any reference to read it in place.
Quotation4
A formal citation — high verbal volume, often introduced by a saying-formula.
The climactic citation that seals the book: 'Go to this people and say, In hearing you will hear but not understand... lest they turn and I would heal them.' Acts 28:26-27 reproduces LXX Isaiah 6:9-10 almost verbatim, explicitly attributed ('the Holy Spirit spoke rightly through Isaiah the prophet'). Maximal volume and an introductory formula — the keystone quotation.
High confidenceJesus directly cites Isaiah's commission, 'seeing they may not see, and hearing they may not understand,' to explain why he teaches in parables. The verbal dependence is explicit and abbreviated from the LXX, giving maximal Volume, Recurrence (a key NT text), and Availability.
High confidenceMark 4:12 directly quotes Isaiah's commission ('seeing they may see, and not perceive; hearing they may hear, and not understand; lest they should turn and be forgiven'), with the wording closer to the Targum's 'be forgiven' than the MT/LXX 'be healed.' This is the chapter's central formal citation: high volume, explicit, and thematically governing the entire purpose-of-parables saying.
High confidenceFormal fulfillment quotation (v.14-15): 'hearing you will hear and not understand, seeing you will see and not perceive... this people's heart has grown callous.' Verbatim LXX citation explaining why parables both reveal and harden.
High confidenceAllusion2
A deliberate verbal borrowing without a citation formula.
God's judicial hardening so that the people hear but do not understand underlies Paul's 'God sends them a working of error, that they should believe a lie.' The motif of divinely-sent blindness on those who reject truth is central.
High confidenceJesus' rebuke 'Having eyes, don't you see? Having ears, don't you hear?' directly applies Isaiah's commission oracle of a people who see but do not perceive and hear but do not understand. Mark already cited this text at 4:12; recurrence and verbal closeness make this a strong, deliberate appropriation now turned on the disciples themselves.
High confidenceEcho4
A fainter, low-volume reuse, carried by recurrence or thematic coherence.
The hardening of those who hear the word, leading the messenger to turn elsewhere, echoes Isaiah's commission to a people whose heart is made fat and will not understand. Luke cites this text explicitly in Acts 28 as the climactic interpretation of Jewish unbelief, making it a recurring lens here. Coherence high; verbal contact in this pericope is allusive.
Medium confidenceThe 'eyes that do not see, ears that do not hear' hardening language of v.8 also resonates with Isaiah's commissioning oracle ('hearing you will hear and not understand; seeing you will see and not perceive'), the classic hardening text. Reinforces the conflated citation's theme even if Deut 29:4 supplies the closer wording.
Medium confidence'A partial hardening has happened to Israel, until the fullness of the Gentiles has come in' (v.25) sustains the Isaianic hardening motif of the chapter (cf. the Isa 29:10 citation at v.8). The temporal 'until' frames the hardening as the bounded judicial blindness of Isaiah's commission.
Medium confidence'Hear but do not understand... lest they understand with their heart' — the hearing/understanding/heart cluster ironically inverted in Jesus' 'Hear and understand' (15:10) and the disciples' dullness (15:16).
Low confidence◇ Figural2
A typological pattern re-read in a later text — no verbal quotation, high figural coherence.
'I came for judgment, that those who don't see may see, and those who see may become blind' inverts and fulfills Isaiah's commission to blind the seeing and deafen the hearing. John elsewhere cites Isaiah 6:10 explicitly (12:40), making this the controlling intertext for the chapter's sight/blindness-as-judgment theme. High Recurrence and Coherence.
High confidenceThe two-stage cure—first blurred ('men like trees walking'), then clear sight—dramatizes the half-perceiving condition diagnosed by Isaiah's seeing-but-not-perceiving oracle. Mark figures the disciples' gradual, incomplete recognition of Jesus through the man's gradual healing; the structural coherence is strong even without verbal quotation.
Medium confidence