Midrash for Yevamot 124:5
התם דחויי קמדחי להו דרב ששת איעקר מפירקיה דרב הונא
'Marry a wife and beget children', and he answered them, 'My daughters' children are mine'! — There he was merely putting them off, because R. Shesheth became impotent owing to the long discourses of R. Huna.<span class="x" onmousemove="('comment',' The discourses being long, R. Shesheth, in his desire not to interrupt them, suppressed his needs and thus impaired his generative organs. V. Bek. 44b. ');"><sup>11</sup></span> Said Rabbah to Raba b. Mari: Whence the statement made by the Rabbis that grandchildren are like children? If it be suggested that it is deduced from the Scriptural text, The daughters are my daughters and the children are my children,<span class="x" onmousemove="('comment',' Gen. XXXI, 43. ');"><sup>12</sup></span> would then [it may be objected] the same [meaning be given to the text] And the flocks are my flocks?<span class="x" onmousemove="('comment',' Gen. XXXI, 43. ');"><sup>12</sup></span>
Kohelet Rabbah
“In the morning, sow your seed” – Rabbi Eliezer and Rabbi Yehoshua: Rabbi Eliezer says: If you sowed early in the season, sow [another field] late in the season, as you do not know which will endure for you, the early or the late. “As you do not know which will succeed, whether this or that.”
Rabbi Yehoshua says: If you married a woman in your youth and she died, marry in your old age. If you had children in your youth, you should have children in your old age, as it is stated: “In the morning, sow your seed, and in the evening do not rest your hand, as you do not know which will succeed, whether this or that.”
Rabbi Yishmael and Rabbi Akiva: Rabbi Yishmael says: If you studied Torah in your youth, study in your old age, as you do not know which Torah will endure, that of your youth or that of your old age, “or whether they both alike will be good.” Rabbi Akiva says: I had twelve thousand students from Gevat to Antipatris, and they all died during my lifetime, between Passover and Shavuot. Ultimately, seven promulgated my [Torah],35Seven students whom I taught in my old age were responsible for dissemination of my Torah. and these are they: Rabbi Yehuda, Rabbi Neḥemya, Rabbi Meir, Rabbi Yosei, Rabbi Shimon ben Yoḥai, Rabbi Eliezer son of Rabbi Yosei HaGelili, and Rabbi Yoḥanan the cobbler. He said to them: The first ones died only because they were begrudging to each other regarding their Torah. Do not be like that. They quickly rose and filled all of the Land of Israel with Torah.
Rabbi Natan