The culmination of a careful deception unfolds as a foreign king becomes entirely convinced of an Israelite exile's absolute loyalty. Achish, the king of Gath, naively believes the reports brought before him, trusting that David is constantly raiding and provoking his own people. The commentators explain that David's actions are perceived as creating a deep, irreversible disgust. He has completely ruined his relationship with the Israelites, making himself as repulsive to them as a foul odor [מצודת ציון, רד״ק, ביאור שטיינזלץ].
Achish bases his confidence on a careful analysis of the political and social landscape. He concludes that the hostility toward David is no longer limited to King Saul but has spread throughout the entire nation [אברבנאל]. Furthermore, Achish assumes that David has not merely attacked rival tribes to win favor with his own, nor has he fought his own tribe to appease others. Instead, he believes David has alienated everyone simultaneously. By supposedly attacking both Judah and the Kenites, David has destroyed his standing in the eyes of the entire nation, leaving himself without a single supporter [מלבי״ם].
Because of this assumed reality, Achish deduces that David defected to the Philistine side out of sheer necessity. Having burned all his bridges, David can never return to his people. Therefore, he is bound to remain permanently loyal to his new king and will never abandon his post [ביאור שטיינזלץ, אברבנאל].
This paradoxical situation, in which a Philistine king deeply trusts, elevates, and cares for an Israelite leader, highlights a deeper reality. It reflects the divine providence constantly accompanying David, showing how God's grace can cause even a person's enemies to make peace with him [אברבנאל].