Midrash for Yevamot 124:7
אלא מהכא (דברי הימים א ב, כא) ואחר בא חצרון אל בת מכיר אבי גלעד ותלד לו את שגוב וכתיב (שופטים ה, יד) מני מכיר ירדו מחוקקים וכתיב (תהלים ס, ט) יהודה מחוקקי
and furthermore it is written, Judah is my lawgiver.<span class="x" onmousemove="('comment',' Ps. LX, 9. As this text implies that the lawgivers were descendants of Judah, Machir (Judges V, 14), a descendant of Manasseh, could not have been the paternal, but only the maternal ancestor of the lawgivers that descended from him. The lawgivers were thus the offspring of the union mentioned in I Chron. II, 21, between Hezron, a descendant of Judah, and a daughter of Machir. This then proves that the sons of one's daughter are also regarded as one's own sons. ');"><sup>16</sup></span> Our Mishnah<span class="x" onmousemove="('comment',' Which permits abstention from further propagation after the birth of the prescribed number of children. ');"><sup>17</sup></span> cannot represent the opinion of R. Joshua. For it was taught: R. Joshua said, If a man married in his youth, he should marry again in his old age; if he had children in his youth, he should also have children in his old age; for it said, In the morning<span class="x" onmousemove="('comment',' I.e., 'the morning of life', youth. ');"><sup>18</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