שופטים, פרק ט״ז, פסוק כ״ה

In the midst of their victory celebration, the Philistines were in exceptionally high spirits. This elevated mood was fueled both by heavy eating and drinking [מצודת דוד] and by the sheer joy of their triumph [ביאור שטיינזלץ]. Swept up in the revelry, the crowd demanded that their humiliated captive be brought from prison to serve as their entertainment. Their intention was to mock Samson, forcing him to amuse them and perform whatever tasks they commanded [ביאור שטיינזלץ].

Brought out before the crowd, Samson played along, amusing the Philistines much like a jester. He entertained them, with some suggesting that he did so by recounting his past acts of heroism [מצודת דוד]. To ensure the massive audience could watch the spectacle, the Philistines positioned him exactly in the middle of a very large building [ביאור שטיינזלץ]. Specifically, he was placed between the central pillars, the primary structural foundation upon which the entire building rested [רש״י].