The Greek word pule refers to a large gate — the great gate of a city, a palace gate, or the gate of Hades. It is to be distinguished from thura (G2374, door) which is smaller. Pule often carries strategic or symbolic significance: gates were the locus of authority, judgment, commerce, and military defense in the ancient world.
The theological significance of pule in the New Testament is concentrated in two uses: the 'narrow gate' of Matthew 7:13-14 and the 'gates of Hades' of Matthew 16:18. In the first, Jesus presents two gates — the narrow gate leading to life and the wide gate leading to destruction — a decisive call to costly discipleship over comfortable religion. In the second, Jesus declares that the gates of Hades will not overpower His church — a promise of resurrection triumph. In ancient siegecraft, if a city's gates fell, the city fell; Jesus declares that death's gates will not withstand the advance of His church. Pule is thus the word of divine authority and the call to decisive entry through the narrow way.