דניאל, פרק ה׳, פסוק ו׳

In the midst of a wild and joyous royal feast, a sudden supernatural event paralyzes the king with terror. The shocking sight causes a complete physical and mental collapse, stripping him of all his royal dignity.

Naturally, drinking wine brings a bright and happy glow to a person's face. However, confronted with this terrifying vision, the king loses not only the warmth brought on by the wine but his natural royal majesty as well. His face turns completely dark, resembling the blackened bottom of a cooking pot [אלשיך]. This extreme physical change, where his face literally loses its color, proves to the king that what he is seeing is a real occurrence and not just a trick of his imagination [מלבי״ם].

This physical collapse is matched by a deep psychological crisis, as his own thoughts begin to terrify him. Usually, a person startled by a sudden event tries to calm down with positive thinking, hoping the situation might bring good news. Instead, the fear of God falls heavily upon the king. The very thoughts he relies on for comfort turn against him, amplifying his anxiety and leaving him with no hope [אלשיך]. Deep down, he immediately understands that the vision is a dark omen [מלבי״ם].

The sheer intensity of his panic leads to a complete loss of bodily control. His waistband comes undone, symbolizing a profound loss of stability and severe weakness [שטיינזלץ], to the point where his bowels empty from sheer fear [רש״י]. While some view the loosening of his joints as a deliberate exaggeration meant to show the massive scale of his anxiety [מצודת דוד], others explain that his belt actually opens on its own. In the eyes of ancient nations, such an occurrence is considered an especially terrible sign [מלבי״ם].

Ultimately, the king experiences uncontrollable shaking. His knees knock together violently from his overwhelming dread [מצודת ציון]. This intense, repetitive striking of his knees is poetically compared to the image of a woman repeatedly kissing her sister [אבן עזרא].