The assassination of the Moabite king reaches its dramatic climax in a single, violent, and highly precise strike. Thrusting his weapon with immense force, the assassin buries the sharp, polished iron blade—shining brightly like a flame—deep into the heavy-set king's body [רש"י, מצודת ציון, רד"ק, ביאור שטיינזלץ]. The strike is so forceful that the handle follows the blade entirely into the flesh. This deep penetration is a calculated move designed to kill the king instantly, preventing him from crying out and alerting his guards [מצודת דוד].
Because the king is exceptionally overweight, his thick layers of body fat completely close over the length of the buried weapon [רש"י, רד"ק, ביאור שטיינזלץ]. The assassin does not pull the sword back out, a detail that commentators explain in several ways. Some suggest that the sheer mass of fat physically traps the weapon, making it impossible to withdraw [רלב"ג, רד"ק]. Others view this as a deliberate choice; leaving the weapon inside prevents blood from splattering onto the assassin's clothes, ensuring he can flee without looking suspicious [מצודת דוד, מלבי"ם]. Another perspective notes that the thick layer of fat makes it difficult to tell if the blade has actually pierced the vital organs. To be absolutely certain of the kill, the assassin continues pushing the handle inward until the body cavity ruptures, confirming the assassination is successful without ever needing to remove the blade [רלב"ג].
The primary approach among commentators is that as the belly splits open, the king's bodily waste spills out [רש"י, מצודת ציון, רד"ק, מלבי"ם, ביאור שטיינזלץ]. While a minority opinion once suggested this description referred to the assassin himself exiting into a guards' waiting room, this idea is rejected. The subsequent events clearly state the assassin leaves through a corridor, proving that the initial exit refers to the king's ruptured intestines rather than the assassin's movements [רד"ק, מלבי"ם]. This gruesome biological outcome ultimately plays a crucial role in the escape. The foul smell seeping from the room leads the king's servants to assume he is merely relieving himself in private. This simple misunderstanding buys the assassin the precious time he needs to slip away unnoticed [מצודת דוד, מלבי"ם].