“And there was a famine in the land, aside from the first famine that was in the days of Avraham...And G-d appeared to him [Yitzchak] and said: Do not go down to Egypt, dwell in the land that I will tell you” (Breisheet 26:1-2).
It is quite clear that this famine was not the same one that occurred during the days of Avraham. Approximately 100 years had lapsed since Avraham went to Egypt searching for food. Presumably, Avraham returned to Israel only when the famine ended, and the Torah spends many a verse describing the meals both Avraham and Lot prepared for their unexpected guests.
Moreover the Torah, in the immediately preceding verse, records how Yaakov and Eisav ate and drank together to “celebrate” the sale of the birthright. The Torah had previously noted that "their [Avraham’s and Lot’s] wealth was so great that the land could not support them" (Breisheet 13:6). Surely, whatever famine there was when Avraham arrived in the land was long over.
G-d's command to Yitzchak that he, unlike his father, is not to go to Egypt for sustenance is also difficult to comprehend. There is absolutely no indication in the text that Yitzchak was planning such a trip. The Torah notes that Yitzchak “went to Avimelech in Gerar.” This is a most logical choice, as the last mention of Avimelech is the treaty he made with Avraham. A time of famine is a most opportune time to take advantage of such a treaty. When one considers that Avraham had been thrown out of Egypt, there is little reason to believe Yitzchak had any intention of travelling to Egypt.
The Torah, in describing this second famine, is not passing along the latest in farm reports. Rather, the Torah is stating the inherent difference between the land of Egypt and the land of Israel. “The land which you are about to inherit is not like Egypt, the place you left, where you plant your seed and irrigate it by yourself. The land you are coming to inherit...is a land dependent on rain” (Devarim 11:10-11). Famine in the land is part and parcel of its terrain. The constant specter of famine is a necessary—though harsh—way of teaching that to inherit the Land of Israel means to be dependent on G-d for our sustenance. And if our sustenance comes too easily, we are liable to lose sight of that fact.
G-d's instruction to Yitzchak not to go to Egypt is not a temporary travel advisory, or some kind of promise that the famine would end soon. It reflects the fundamental difference between father and son. Avraham, who traversed the length and breadth of the ancient world, would face no negative impact visiting the cultural, technological and political centre of the ancient world. As Rav Soloveitchik notes, such exposure would actually strengthen the resolve of our founding father. Seeing the moral depravity of Egypt, experiencing the kidnapping of his wife, he realized that his theological revolution was also a moral one – one explicitly noted later when the Torah tells us that G-d chose Avraham because he would teach his children "righteousness and justice" (Breisheet 18:19). He returned to Israel more determined than ever to spread his moral message. Sadly, he then realized that he must part ways with Lot, as his nephew no longer shared his sharpened moral vision.
For Yitzchak, a trip to Egypt risked disaster. Lacking the worldliness of his father, exposure to the Egyptian way of life could have had a disastrous moral impact on him. The chasm between willingly offering oneself as a sacrifice to G-d and the ways of Egypt would be too wide to bridge. Even his journey to Gerar was a most difficult one. Here, for the first time, Yitzchak faced jealousy, anti-Semitism, and expulsion from the land.
That he was shaken up by the experience is evident from the fact that immediately thereafter G-d appears to Yitzchak telling him not to be afraid (Breisheet 26:24). His ensuing reconciliation with Avimelech brings only short-term relief and is followed with Eisav causing much grief to his parents through his choice of wives. Yitzchak prepares for death and is soon seized with fear and trembling, realizing he has been tricked by his children. He sends Yaakov away to find a wife in Lavan's home, and while he lives for many more years—through the sale of Joseph to Egypt—the only other mention of Yitzchak is his death.
Our Sages identify Yitzchak with the trait of gevurah, spiritual strength. It was not easy for him to be forced out of his idyllic existence of meditating in the fields. It was not easy for Yitzchak to see the world as it is, to see that trickery and evil are part and parcel of this world. And that was without being exposed to Egypt! It was he, more so than Yaakov, who actually "dwelled in the tent”, seemingly oblivious to the world around him.
While Egypt had an important role in the life of his father and that of his son, the role of Yitzchak was different. While father and son sought to transform evil, Yitzchak sought to avoid it, to dwell in the “good land that He has given you”.