The sudden, extreme wealth of a foreigner within a local society often disrupts the political and social balance, triggering a fierce backlash. When Isaac achieves massive economic success among the Philistines, it exposes deep political, economic, and spiritual tensions that culminate in a demand for his expulsion. This banishment is viewed by some as a blatant violation of the peace treaty previously established with Abraham, exposing the emptiness of such political agreements [ברכת אשר על התורה]. It also stands as an early symbol of future exile, foreshadowing how nations would later restrict where the Jewish people could live [העמק דבר].
Conversely, other commentators suggest that King Abimelech approached Isaac peacefully and out of genuine concern. The king did not expel Isaac from the entire country, but only from the royal city. Fearing that his jealous ministers and citizens might harm Isaac or incite a rebellion, Abimelech suggested he relocate for his own safety [שד״ל, ביאור יש״ר]. Nevertheless, the underlying issue was Isaac's overwhelming power. His vast fortune was perceived as a severe political and military threat, with locals fearing he might use his wealth to fund an uprising [ספורנו]. Furthermore, Isaac's immense status completely overshadowed Abimelech, creating a humiliating dynamic where the monarch's glory was eclipsed by the wealth of a single citizen [אור החיים, ביאור שטיינזלץ].
The local population viewed Isaac's prosperity with intense resentment, feeling either that he had simply grown vastly richer than them, or worse, that his wealth was built entirely at their expense [רד״ק]. Denying God's providence, they attributed his success to natural causes, claiming he had profited off their suffering by selling grain during the famine [רד״ק, הכתב והקבלה]. Others were driven by pure greed, hoping to confiscate Isaac's land. They mistakenly believed the soil itself was naturally blessed with extraordinary fertility and wanted to remove him to take control of it [ריב״א, חזקוני].
On a spiritual level, the Philistines suspected that Isaac was absorbing all the abundance and good fortune meant for them. They also worried that his presence caused God to compare Isaac's good deeds against their bad ones, thereby withholding blessings from the locals [אלשיך]. They failed to realize that a righteous person functions like a heart in a human body: while it draws in the lifeblood, it immediately pumps that vitality outward to nourish all the surrounding limbs [מלבי״ם]. Only after Isaac departed and the locals saw their own fields fail did they realize their terrible mistake. They were forced to admit that the agricultural success was not natural to the land, but stemmed entirely from God's personal blessing upon Isaac [ריב״א, הכתב והקבלה, אלשיך].
From a broader historical perspective, the jealousy of the Philistines and the subsequent expulsion served a higher divine purpose. This social rejection saved Isaac from the dangers of assimilation, preventing him from blending into the Philistine upper class. By being pushed away, he was forced to maintain his unique spiritual destiny. This protective mechanism of social isolation would continue to preserve the identity of the Jewish people throughout history [רש ר הירש].