Or HaChaim on Genesis 15:16/אור החיים על בראשית ט״ו:ט״ז

1 ודור רביעי ישובו הנה, "And the fourth generation will return here, etc." We must examine why the extent of the sins of the Emorite has a bearing on the timing of Israel's return to its homeland. Rashi and Nachmanides disagree on what the words "the fourth generation" refer to. Rashi understands them as a reference to the fourth generation from Yehudah (who descended to Egypt). His son was Peretz, his grandson was Chetzron; great grandson Caleb returned to the land of Israel. Nachmanides rejects Rashi's explanation preferring to understand the words as referring to a fourth generation of Emorites. He bases himself on G'd waiting up to four generations before visiting the sins of the fathers on their descendants (Exodus 34,7). Even if we accept the words of Nachmanides, why did G'd mention this fact to Abraham? Besides, it appears that no provision was made for the possible penitence of the Emorite, which, according to Nachmanides, would have delayed a return of the Jewish people to their homeland still further? Furthermore, assuming that Nachmanides is correct, why did G'd mention the sin of the Emorite altogether once He had told Abraham that the Jewish people would return to their homeland in the fourth generation?

2Actually, G'd told Abraham of two possible timetables according to which the return of his descendants to the land of Canaan could occur. One is the end of the exile in Egypt and the oppression there. This would occur when the combination of the years of being a stranger, being enslaved, and finally being oppressed (עינוי), would total 400 years. At that point G'd's decree would have been completed and He could lead the Jewish people forth from Egypt on the very day that those years came to an end. The second time factor which would enable the Jewish people to return to their homeland would be determined by the measure of guilt the Emorites had accumulated by that time. This would occur in the fourth generation, a generation later than the Exodus. For the purpose of this calculation the generation of Caleb is considered the third generation inasmuch as Caleb left Egypt as an adult. Even though Caleb personally entered the Holy Land (Numbers 14,30), the entry of a single Jew certainly does not constitute the return of a people to their homeland. When the Torah speaks about a generation it refers to the majority of the members of that generation. Caleb's sons constituted part of the fourth generation, as did all those who had not attained the age of 20 prior to the Exodus. The four generations are not to be counted as commencing with Yehudah, as does Rashi. If we were to count in Rashi's fashion i.e. from the time G'd's decree became effective, there is no reason why Isaac himself should not be considered as a generation either, seeing that the 400 years commenced with his birth. If, on the other hand, we are to count the generations as commencing with the first Jew who descended to Egypt, the count should commence with Jacob. If we did this, Caleb himself would already be the fifth generation. It is clear then that the count was meant to commence with the period the Israelites experienced enslavement. Shemot Rabbah 1,5 states that as long as any of Joseph's brothers was alive none of the Israelites were enslaved. The calculation of the fourth generation the Torah speaks about here therefore commences with Yehudah's sons Peretz and Chetzron.

3The fact that the Torah uses the plural when speaking about the return of the Jewish people is a hint that the Torah speaks about people who have been forcibly prevented from returning up until that time. They would return after four generations have been completed. The first generation of Israelites who were forcibly prevented from returning to the land of Canaan were the children of Joseph and his brothers.

4We now need to understand why the guilt of the Emorite plays any role in all this when the Torah elsewhere told us in Numbers 14 that the sin of the spies and the generation who believed the ten spies was the cause that re-entry to the land of Israel was delayed by an additional generation. The 400 years G'd had decreed were completed at the time the Jewish people asked that the spies be sent out. Had they not done so, they would have entered the land of Israel at the end of the 400 years G'd speaks about in our פרשה. This would have coincided with the 3rd generation of the Jews who had experienced servitude. The additional generation was due to the sin of the spies. Assuming this tragic delay had not occurred, how could G'd have squared entry of the Jewish people to the land of Canaan with the measure of guilt of the Emorites the Torah speaks about here?

5We must understand the Torah in terms of how the Talmud Berachot 7 explains Chabakuk 1,13: למה תביט בוגדים, תחריש בבלע רשע צדיק ממנו, "Why do You countenance treachery, and stand by idly when the one in the wrong devours the one in the right?" The Talmud says that while it is possible that the wicked triumphs over someone relatively more righteous than he, he will never triumph over someone truly righteous. This means that the wicked are not totally devoid of merits, and we find on occasion that by using their merit they can overcome someone else who is generally more pious than they (while on this earth). The reason is that the wicked at that time can point at the imperfections of the person who thinks of himself as righteous. When the wicked is absolutely wicked however, it is not only permissible to destroy him but whichever righteous person does so first deserves credit. One need not be a totally righteous person in order to be entitled to wipe out such a wicked person.

6At the time of the Exodus as well as at the time when they despatched the spies about 15 months later, the Israelites were on the level of perfectly righteous people. Although they had sinned during the episode of the golden calf, they had been punished for that sin and had regained their status as צדיקים גמורים, as perfectly righteous people. The "echo" of that sin was not strong enough to deprive them of that title especially vis-a-vis the Emorites. In Sanhedrin 110 Rabbi Eliezer describes the people at that time as pious, quoting Psalms 50,5: "bring in My devotees, who made a covenant with Me over sacrifice" as his support. After the episode with the spies, Israel lost this status. From that moment on their moral superiority over the Emorites was marginal. As long as they had been considered חסידים their merit was enough to overcome the Emorites immediately. If the Emorites had refused to vacate the land in order to allow Israel to return there, they could have easily overcome them in battle. Now they had to wait until the Emorites accumulated a further measure of sin before their own moral superiority would suffice to overcome the Emorites in their homeland. Proof of our contention is found in Numbers 14,44 when the Israelites had realised that they had sinned grievously in fearing the Canaanites, and volunteered to fight them. Moses warned them against such an enterprise. They insisted and were defeated. Had they been considered as righteous they certainly would not have been defeated. All of this is an elaboration of what the prophet Chabakuk spoke about.

7The point is underscored by Moses in Deut. 9.5, where Moses credits Israel's conquest of the land of the Canaanites not to their piety but to the wickedness of the inhabitants of that land at that time. Moses meant that the measure of their sins had become full by that time. Moses told the Israelites at that time that though they were not totally righteous, their merit was sufficient to overcome the complete lack of it in their opponents. He emphasised this lack of righteousness by the Israelites three times! However, the Emorites had absolutely no merits left that they could have used to help them triumph against Israel's various moral shortcomings.

8We now understand the need for mentioning the "fourth generation" in G'd's promise in our verse. G'd stated that the latest possible date for Israel taking over its inheritance would be at the end of four generations since the onset of slavery. By that time the Emorites would not have any merit left they could use to deny Israel their return to the land of their forefathers. This part of the prophecy would become relevant only if Israel did not maintain sufficient moral superiority over the Canaanites, if they did not qualify for the appellation צדיק גמור.