At the beginning of Parshat Toldot, Yitzchak goes to Gerar because of a famine. While there, Hashem comes to him and says (Bereishit 26:2), “Al Teireid Mitzraimah,” “Do not descend to Egypt.” Rashi explains that Yitzchak was forbidden to go down to Mitzrayim because he was considered a Korban. Each Korban has its own area that it is not allowed to leave. Yitzchak’s area was Eretz Yisrael, so he could not go down to Mitzrayim.
The Chidushei Harim wonders why Yitzchak couldn’t he leave Eretz Yisrael. After all, a Korban is only forbidden to be removed from its area after is has been slaughtered and all of its procedures have been performed. Since Yitzchak was not actually slaughtered, why was he forbidden to leave Eretz Yisrael?
The answer is that according to Rashi, Hashem never intended for Avraham to slaughter Yitzchak. He said only (Bereishit 22:2), “VeHaaleihu Sham LeOlah,” “Bring him up as an Olah offering.” Therefore since he was already brought up to the mountain, his service had actually been completed and he now had the status of a Korban. Therefore, Yitzchak was forbidden to leave Eretz Yisrael.