מלכים א, פרק ט״ז, פסוק כ״א

The death of a ruler often brings hidden political tensions to the surface, leading to a bitter struggle for the throne. In this instance, the timing of the national split among the Israelites was highly specific. As long as Zimri was alive, the people maintained a united front to prevent him from establishing his rule. Even those who did not actually want Omri to lead refrained from breaking away. However, the moment Zimri died, this temporary and fragile alliance shattered, and the underlying conflict broke out into the open [מלבי״ם].

The nation divided into two distinct factions. One half threw its support behind Omri. The other half, made up of everyday citizens who were not part of the military camp, chose to follow Tibni son of Ginath with the goal of making him their king [מצודת דוד, ביאור שטיינזלץ].

This deep divide within the nation was not a brief disagreement; the standoff lasted for four full months [רד״ק]. The bitter struggle was ultimately decided only with the death of Tibni. Whether he died of natural causes or was killed in the ongoing conflict, his passing finally cleared the path for Omri to take the throne and rule over the entire nation without further opposition [אברבנאל].