דברי הימים א, פרק י״ג, פסוק ט׳

The grand procession to transport the Ark encounters a sudden and dangerous crisis, triggering an instinctive reaction with fatal consequences. As the convoy travels, it arrives at a location known as the threshing floor of Chidon [רש״י, ביאור שטיינזלץ]. In a parallel historical account, this same site is referred to as the threshing floor of Nachon. This difference is generally resolved by understanding that the location simply went by two different names [מצודת ציון, רד״ק]. Alternatively, the name Chidon—a word implying ruin and loss—might have been given to the area only retroactively, forever marking the site of the tragic disaster that was about to unfold [רד״ק].

The crisis begins when the oxen pulling the transport cart jerk abruptly, causing the wagon to shake violently back and forth [מצודת ציון, ביאור שטיינזלץ]. Because the cart carrying the Ark appears to have been an open platform without protective side walls, this sudden jolting creates a very real and immediate danger that the Ark will slip off the edge and crash to the ground [מצודת דוד, ביאור שטיינזלץ].

Seeing the sacred object on the verge of falling, Uzza reacts with a quick, natural instinct. He extends his hand to stabilize the Ark and prevent it from tumbling down [מצודת דוד, ביאור שטיינזלץ]. The precise description of his action focuses entirely on his intention to hold the Ark. This specific detail clarifies a slight variation in the parallel historical account, which states that he actually took hold of it. The subtle distinction here highlights that the fatal consequence was triggered by the very act of extending his hand toward the Ark, striking him down before he could even make physical contact [מלבי״ם].