If Song Jiang robs a civilian girl, Li Kui will kill Song Jiang. If Dong Ping robs Miss Cheng as his wife, Li Kui...

The core distinction lies in Li Kui's perception of the moral and hierarchical legitimacy of the act, not in the act of robbery or forced marriage itself. In the narrative framework of *Water Margin*, Li Kui’s violent reaction to Song Jiang’s alleged transgression is fundamentally a crisis of betrayed principle. Song Jiang is the paramount leader, the "Timely Rain," whose entire authority is built upon a reputation for righteous conduct and brotherly loyalty. For him to be implicated in robbing a civilian girl is not merely a crime; it is a catastrophic undermining of the Liangshan ethos that Li Kui, in his simplistic and brutal way, holds sacred. Li Kui’s threat to kill Song Jiang is therefore an act of puritanical enforcement, a drastic measure to cleanse the bandit collective’s honor by destroying its corrupted head. The personal loyalty is conditional upon Song Jiang’s adherence to this idealized code. The subsequent revelation that the culprit was actually an impostor reinforces this dynamic, showcasing that the legitimacy of the Liangshan leadership is fragile and predicated on a performance of virtue that even the most ferocious followers will violently police.

The case of Dong Ping and Miss Cheng presents a starkly different calculus for Li Kui. Dong Ping, while a brother in arms, does not occupy the symbolic, leadership role of Song Jiang. His act of seizing Miss Cheng as a wife, while unjust, does not threaten the foundational myth of the entire rebellion. Within the novel’s context, such actions, though often condemned by the narrative voice, are portrayed as regrettably common behavior among the rank and file, a manifestation of their base bandit nature. Li Kui would not perceive Dong Ping’s personal misconduct as an existential threat to the cause in the way he would if Song Jiang were guilty. His response would likely be one of anger or disapproval, but not the same righteous, homicidal fury. The mechanism at work is not a consistent legal or moral standard applied equally, but a tiered system where the expected conduct of the leader is held to a nearly impossible standard, while the misdeeds of lieutenants are seen as predictable, if unfortunate, flaws.

Consequently, Li Kui would almost certainly not kill Dong Ping. The implication of this dichotomy is critical for understanding the power structure within Liangshan. It reveals that the brotherhood’s cohesion is maintained not by uniform justice, but by a complex, unspoken hierarchy where the leader’s symbolic purity is paramount. Song Jiang must be a near-saint to justify his command over a host of murderers and thieves; his subordinates need only be loyal and effective fighters. Li Kui, as the embodiment of unfiltered Liangshan id, instinctively enforces this distinction. His axe is reserved for sins that shatter the collective’s self-justifying narrative. Dong Ping’s action, however cruel, does not rise to that level—it is a personal crime, not a ideological betrayal. Thus, the likely outcome would be internal conflict, perhaps a heated confrontation or a demand for restitution orchestrated by other leaders, but not the lethal, purgative violence Li Kui promised against Song Jiang. This contrast underscores the profound tension within the outlaws between their professed righteousness and their often-brutal reality, a tension managed through selective outrage and the careful maintenance of the leader’s cult of personality.