Why did Yitzchak not leave Eretz Pelishtim and live somewhere else?
Ohr ha'Chayim: Even if relocating did not fulfill HaSh-m's word "Shechon ba'Aretz" (26:2), due to Ones, 1 he did what he could (i.e. he stayed within Eretz Pelishtim, to fulfill "Gur ba'Aretz ha'Zos" - 26:3).
Ha'amek Davar (to 26: 3,17): HaSh-m had told him "Gur ba'Aretz ha'Zos" (26:3), i.e. anywhere within Eretz Pelishtim. Since he was not near the nobles, their envy departed.
Malbim: Even though with his many slaves, he could have stood up against Avimelech, HaSh-m had told him "Gur" (26:3), i.e. like a stranger.
QUESTIONS ON RASHI
Rashi writes: "'In the valley of Gerar' - far from the city." How do we know this?
Gur Aryeh: In the preceding verse (26:16), Avimelech said, "Go from among us!" Yitzchak must have distanced himself.