Yitzchok and Rivka's Prayers: The Value of a Tzaddik Ben Rasha

Rabbi Zweig addresses a fundamental question arising from the halachic principle that a tzaddik ben tzaddik (righteous person from righteous parents) is preferred as a shaliach tzibbur (prayer leader) over a tzaddik ben rasha (righteous person from wicked parents). The Magen Avrohom maintains this hierarchy, while the Taz argues that a tzaddik ben rasha is actually superior because "rachmana liba ba'ei" (God wants the heart)—someone who overcame greater challenges has more merit. The Maharshal takes a middle position. Yet Parshas Toldos states explicitly that Yitzchok and Rivka both prayed for children, and "vaye'etar lo Hashem (ה׳) v'lo lah"—his prayers were answered, not hers. This appears to prove that Yitzchok, a tzaddik ben tzaddik, had superior prayers to Rivka, a tzadekes bas rasha. The difficulty deepens when we notice that immediately before this verse, the Torah (תורה) provides a detailed description of Rivka's lineage: "Rivka bas Besuel ha'Arami miPadan Aram, achos Lavan ha'Arami." Rashi (רש"י) asks why this information is repeated, since we already knew it from the previous parsha. His answer is "lehagid shevachah"—to tell her praise—that despite being the daughter of a rasha, sister of a rasha, and raised among resha'im, she did not learn from their ways. But this creates an internal contradiction: if the Torah just spent an entire verse extolling how extraordinary Rivka was as a tzadekes bas rasha, how can the very next verse diminish her prayers in favor of a tzaddik ben tzaddik?