The answer is: Samuel

1 Samuel 15:32-33 - Samuel completed the job that Saul failed to do

In 1 Samuel, we encounter a poignant moment in the history of Israel as God’s chosen people grapple with their identity and leadership. King Saul, the first monarch of Israel, received direct commands from God through Samuel—the prophet and judge. But when Saul faltered in carrying out his orders concerning the Amalekites, it set the stage for an important turning point.

In contrast to Saul, Samuel steps in and completes God's directive by confronting Agag, the Amalekite king. This poignant act has layers of significance. One interesting layer is the symbol of integrity; while Saul chooses a path of mercy that defies God's instructions, Samuel's decisive action symbolizes fidelity to divine command.

Samuel’s reluctance to kill Agag might stem from an understanding of the greater spiritual implications of warfare and judgment, echoing a theory that personal mercy can conflict with a perceived greater justice. The text tells us that when Samuel does end Agag, he does so with deep somberness, highlighting the gravity of his action—the death of a ruler, not just a victory in battle.

Moreover, we can draw fascinating parallels to later lives in biblical narrative; both David and Jesus handle conflicting commands and challenges from their respective leadership contexts. The binding nature of duty towards divine instruction remains central throughout scriptural accounts, demonstrating a timeline of humanity's struggle with moral obligations versus human compassion.

So next time you read this story, reflect not just on the action but the heavy burden of leadership that intertwines every decision. That’s a lesson that reverberates through time!