Strong’s Greek 2576 (ἐκάμμυσαν / καμμύω) appears twice in the New Testament, both times in direct quotation of Isaiah 6:9-10: Matthew 13:15 and Acts 28:27. In each setting the verb is aorist active—“they have closed”—describing an act of deliberate, self-imposed blindness. Jesus cites the verse while explaining why His teaching ministry includes parables; Paul repeats it to explain Jewish resistance to the gospel in Rome. In both contexts the word marks a decisive human response to divine revelation: rather than an inability to perceive, it is a willful refusal.

Old Testament Background

Isaiah’s “Here am I, send me” commission (Isaiah 6:8-10) frames the prophetic task as one that exposes the spiritual condition of Israel. The Septuagint (LXX) renders “shut their eyes” with the same verb found in Matthew and Acts, forging an unbroken line from eighth-century Judah to first-century Judea and the wider Mediterranean world. This continuity underscores Scripture’s coherence: the hard-heartedness encountered by Isaiah resurfaces in Jesus’ and Paul’s audiences.

Theological Significance of Spiritual Blindness

1. Volitional resistance: The form is middle-voice in classical usage but active in the New Testament; the nuance is still reflexive—people “close their own eyes.” The testimony of Scripture places primary responsibility for spiritual blindness on the human heart rather than on a deficit in divine revelation (cf. Romans 1:18-20).
2. Judicial consequence: While the act is human, God confirms it as judgment. Jesus prefaces the quotation in Matthew 13:13, “For this reason I speak to them in parables,” signaling that parables both reveal and conceal depending on the hearer’s disposition. Paul, quoting the same text, treats Israel’s blindness as a stage in salvation history that opens the door for Gentile inclusion (Acts 28:28; Romans 11:7-11).
3. Hope of reversal: Even within Isaiah’s oracle, a remnant hope remains (“the holy seed,” Isaiah 6:13). Jesus immediately blesses disciples whose eyes do see (Matthew 13:16), and Paul anticipates some being “provoked to jealousy” and returning to faith (Romans 11:14).

Connections to Jesus’ Parabolic Ministry

Matthew situates the quotation amid the Parable of the Sower. The seed is not defective; the soils differ. The closing of the eyes parallels the hardened path that never allows the seed to penetrate. The term therefore illuminates the purpose of parables—to sift responsive listeners from the unresponsive, measuring the heart.

Pauline Usage and Missional Implications

Acts 28 records Paul’s final witness in Rome. After expounding “from morning till evening testifying about the kingdom of God” (Acts 28:23), some are persuaded, others disbelieve. Paul declares Isaiah’s verdict, then announces, “Therefore I want you to know that God’s salvation has been sent to the Gentiles, and they will listen!” (Acts 28:28). The verb ἐκάμμυσαν thus signals a pivot point in redemptive history: Israel’s national rejection occasions the gospel’s wider spread.

Historical Reception in Church Teaching

Early patristic writers, such as Justin Martyr and Irenaeus, cited Isaiah 6:9-10 to explain Jewish unbelief and defend the church’s continuity with the prophetic tradition. Augustine leveraged the verse in discussions of predestination and human responsibility, affirming both divine sovereignty and genuine culpability. Reformation commentators like John Calvin stressed the judicial aspect: God confirms existing hardness yet still calls all to repentance.

Practical Application for Believers Today

• Self-examination: The verb warns against complacent hearing. Regular exposure to Scripture can either soften or harden; the difference lies in humble receptivity (Hebrews 3:7-15).
• Evangelistic realism: Not every listener will respond positively. Faithful proclamation must be coupled with prayer for opened eyes (Ephesians 1:18).
• Intercessory confidence: Because the blindness is self-chosen, it can by grace be undone. The same Spirit who opened Lydia’s heart (Acts 16:14) continues to illuminate.

Related Concepts

– Hardening of heart (σκληρύνω)

– Veil over the heart (2 Corinthians 3:14-16)

– God giving over (Romans 1:24-28)

– Enlightened eyes (Ephesians 1:18)

In sum, Strong’s Greek 2576 pinpoints the moment a person moves from passive ignorance to active rejection of divine truth. Its sparse but strategic New Testament usage frames spiritual blindness as both a human act and a stage in God’s unfolding redemptive plan, calling every generation to keep its eyes open to the light of the gospel.