Yevamos 97b: Yehuda and Tamar: How Was Yibum Permitted?

Why was the story of Yehuda and Tamar permitted before Matan Torah? This episode explores the deeper mechanics of yibum through the lens of the Kovetz Ha’aros: does yibum actively override the prohibition of eishes ach, or is the prohibition itself defined differently when the mitzvah of yibum applies? That question sheds new light on how yibum functioned before the Torah was given—and on the entire story of Yehuda and Tamar.