וְיוֹסֵף֙ בֶּן־שְׁלֹשִׁ֣ים שָׁנָ֔ה בְּעָמְד֣וֹ לִפְנֵ֔י פַּרְעֹ֖ה מֶ֣לֶךְ מִצְרָ֑יִם וַיֵּצֵ֤א יוֹסֵף֙ מִלִּפְנֵ֣י פַרְעֹ֔ה וַֽיַּעֲבֹ֖ר בְּכׇל־אֶ֥רֶץ מִצְרָֽיִם׃
And Yosef was thirty years old when he stood before Pharaoh king of Egypt. And Yosef went out from the presence of Pharaoh, and went throughout all the land of Egypt.
Classical chronological midrash and parallel notices of the age of leadership.
Sefaria · Bereshit Rabbah (context)
וְיוֹסֵף בֶּן שְׁלֹשִׁים שָׁנָה. בֵּן שְׁלֹשִׁים לַכֹּחַ (אבות ה, כא) – וְכָאן עָמַד לְפָנֵי מֶלֶךְ.
English of Core Text: “And Yosef was thirty years old.” “At thirty, for strength” (Avot 5:21) — and here he stood before a king.
On the daf / in context: The tradition notes the correspondence between the age of full strength and the moment Yosef assumes public authority, after thirteen years of slavery and imprisonment.
Type of Learning: Derash on the verse (classic midrash / chronological) — not a formal named middah of the 13.
What Is Learned: Yosef reaches the age of full strength precisely when he is elevated to rule; the years of hardship prepared him for the moment of public responsibility.