παχύνω

I fatten

Definition

The verb παχύνω literally means 'to fatten' or 'to thicken,' describing a physical process. In the New Testament, however, it is used exclusively in a figurative, passive sense, meaning 'to become dull,' 'insensitive,' or 'hardened.' This describes a spiritual and intellectual condition where a person's heart or mind becomes unresponsive to God's truth. This specific meaning is illustrated in its two occurrences, both quoting Isaiah 6:10, where people hear but do not understand and see but do not perceive because their hearts have 'grown dull' (Matthew 13:15, Acts 28:27).

Biblical Usage

This word is used only twice in the New Testament, both times in quotations of the same Old Testament prophecy from Isaiah. It appears in the Gospels (Matthew 13:15) and in Acts (Acts 28:27), in contexts explaining why some people reject the message of Jesus and the apostles. In both passages, it describes the spiritual condition of those who persistently refuse to respond to God's revelation, resulting in a divinely permitted hardening of their own hearts.

Etymology

Derived from the adjective παχύς (pachys, G3976), meaning 'thick,' 'fat,' or 'coarse.' The verb form παχύνω means 'to make thick or fat.' Its figurative development from a physical description to a metaphor for spiritual insensitivity is natural, as something thickened becomes less perceptive and responsive.

Semantic Range

This word is theologically significant as it describes a dangerous spiritual state: a self-induced or divinely-judicial hardening of the heart against God. It underscores the biblical theme of human responsibility in responding to divine revelation. Understanding this Greek term enriches the reading of Matthew 13:15 and Acts 28:27 by highlighting that spiritual dullness is not mere ignorance but an active, culpable condition that prevents repentance and healing.

In the ancient Greco-Roman and Jewish world, physical conditions like fatness or thickness were commonly used as metaphors for slowness, stupidity, or lack of perception. This metaphor would have been immediately understandable to the original audience, linking a physical lack of sensitivity (like calloused skin) to a spiritual inability to comprehend truth.

πωρόω (pōroō, G4456) — to harden, make like stone; often used for a more severe or petrified hardening of the heart. σκληρύνω (sklērynō, G4645) — to harden, make stubborn; emphasizes obstinate resistance.

Word Details

Scripture References