Kommentar zu Bereschit 10:1

AND UNTO THEM WERE SONS BORN AFTER THE FLOOD. The intent thereof is to imply that even though they were fit to have children before the flood — for in those generations it was normal to beget children at about sixty years of age²⁵⁹See above, 5:15, 21. — these did not beget children even at the age of a hundred, only until after the flood, for G-d restrained them from having children in order that they should not perish in the flood or that it [not] be necessary to save many persons in the ark. And so also did G-d do to this entire family: Lamech was delayed in begetting Noah until more than twice the age of his ancestors,²⁶⁰Enoch begot Methuselah at the age of sixty-five (above, 5:21), and Lamech begot Noah at the age of 182 (ibid., Verse 28). Noah begot his sons when he was five hundred years old (ibid., Verse 32). and Noah much more. This is already mentioned in the commentary of Rashi²⁶¹Above, 5:32. who quotes from Bereshith Rabbah.²⁶²26:2.

ואלה תולדת בני נח, who were Shem, Cham, and Yaphet. The ones named after this were their offspring, תולדותם.

ויולדו להם בנים אחר המבול, “children were born for them after the deluge.” Although the fathers and mothers were capable of having children already before the onset of the deluge, G’d had deliberately prevented them from having children in order not to have to destroy their offspring as part of the deluge, and in order not to have to save too many people crowding the ark.