Genèse 10:25

And to Eber were born two sons: the name of the one was Peleg, because in his days the earth was divided; and the name of the other Joktan.

פלג..כי בימיו נפלגה הארץ, this verse informs us of the moral stature of Ever who was able to foresee by means of holy spirit what the future held in store during the lifetime of his son. He called his son Peleg in order to allude to the fact that commencing with his son, man’s life on earth would be drastically shorter. In fact, it was due to the sin committed when his generation built the Tower, that G’d punished them by making them physically weaker so that they aged much more rapidly. The collapse of the Tower was also accompanied by a change in the earth’s climate. (may be not so much the earth’s climate, but the adjustment necessary for the bodies of the people emigrating to regions on earth which had a climate different from that in Mesopotamia)

ולעבר יולד שני בנים, here too the Torah wrote the singular mode yulad, was born, instead of “were born,” as it referred to the general subject of providing progeny, just as in verse 21. We find a parallel construction with Joseph, in Genesis 41,50 וליוסף יולד שני בנים. This does not mean that the people mentioned did not have more than the two sons mentioned, seeing that the Torah specifically mentions (11,15) ויולד בנים ובנות, “he fathered sons and daughters.” The names of the two sons whose births were mentioned here must be understood as being linked to some important experience in the life of their father, who commemorated the event by the way he named these sons.

שם האחד פלג, the Torah immediately supplies the reason for this strange-sounding name, i.e. hardly a good omen, by writing that the split in the unity of mankind when the languages were confused occurred during his lifetime.

ושם אחיו יקטן. In this instance the Torah does not reveal the reason why Ever called his second son Yokton. Our sages surmise that the reason may have been that starting with Yokton, the average lifespan of people became drastically reduced. (Torah Shleymah 59 on our verse) Whereas Ever himself still lived for 464 years, his son Peleg died at 239 years. Not only did he live only a little more than half the number of years his father had enjoyed on earth, but he died while his father was still alive. The names of Ever’s sons are reminders therefore of both the splitting up of a unified mankind into different languages, followed by differing cultures, and into the shorter lifespan which became the order of the day. Apparently, Ever had been aware of this already at the time his sons were born. Clearly, Yokton, even as a baby had been so much smaller than babies had been before his time, that his father had had a premonition that he would not be able to live that long. We had mentioned earlier that the generations that had lived such long lives had also been blessed with much bigger bodies than was the case during subsequent generations. (compare 5,4 and 6,4) According to the view expressed in Seder Olam, and quoted by Rashi, Ever had been a great prophet, equipped with holy spirit, so that he must have predicted all this long before Yokton had been born, seeing that according to the sequence in which matters are reported in our chapter the Tower was built several generations after Yokton had been born already.

פלג. “Peleg.” Rabbi Joseph Kara explains the reason why this son of Ever was called peleg, “division, segment,” was because in his time when the Tower was built and destroyed, the language of mankind, which as the Torah had reported (Genesis 11,1) was uniform and the basis of their unity, was interfered with by G–d, so that eventually there were 70 nations each with a language all their own. At the same time generation after generation man’s lifespan also became drastically shortened. At the time when Peleg was born it had shrunk to about 300 years.