שמואל א, פרק ט״ו, פסוק ח׳

During the campaign against the Amalekites, King Saul carries out the command to wipe out the nation, putting the entire population to the sword. Yet, amidst this total destruction, one man is spared from execution. Instead of facing the same fate as his people, the enemy king, Agag, is actively seized and taken alive as a prisoner [מצודת ציון]. While the rest of the population is systematically destroyed, the king is uniquely preserved [ביאור שטיינזלץ].

The decision to spare the king does not stem from an intentional rebellion against the command, but rather from a fundamental misunderstanding regarding his lineage. Saul is fully aware that the king's mother is an Amalekite. However, he operates under the assumption that a person's national identity is not determined by their maternal line. Based on this logic, Saul concludes that the king does not technically belong to the Amalekite nation, making it permissible to grant him mercy. The flaw in this reasoning lies in the specific rules of lineage that apply to the surrounding nations. Among the nations of the world, national identity is in fact determined strictly by the mother. Consequently, the king is entirely an Amalekite, meaning the obligation to destroy him stands just as firmly as it does for the rest of his people [אהבת יהונתן].