דברי הימים א, פרק י״ב, פסוק ל׳

The transfer of power from the house of Saul to David involved a complex shift in loyalties, particularly within the tribe of the first king. The men of the tribe of Benjamin were closely tied to Saul and were considered his brothers, either because they belonged to his specific tribe [רלב״ג] or because they were his actual blood relatives [מצודת דוד]. When it came time to support David, only three thousand men arrived from this group. While this number was quite small compared to the crowds from other tribes, it is not surprising given their deep prior allegiances [רש״י].

Up until the deaths of the army commander Abner son of Ner and Saul's son Ish-bosheth, the vast majority of the tribe [מצודת ציון] remained fiercely loyal to the house of Saul. They wanted to maintain the kingship within their own ranks, and only a small handful had joined David earlier during his days of wandering in Ziklag [רד״ק, מצודת דוד].

These men from Benjamin were not merely quiet supporters. They actively served as the king's bodyguards, palace watchmen, and closest loyalists [מלבי״ם, ביאור שטיינזלץ]. The true significance of the three thousand men who finally came to David lies in their dramatic shift in allegiance. Despite having been officially appointed to guard and preserve Saul's royal household, they made the deliberate choice to cross the lines. They traveled to David's camp in Hebron, coming entirely of their own free will to crown him as their new king [רלב״ג, ביאור שטיינזלץ].