Why did Isaac not circumcise Esau as soon as he was eight days old?

This source-based Torah study examines: Why did Isaac not circumcise Esau as soon as he was eight days old? It follows the canonical Hebrew discussion through the parasha and classical Jewish sources. This localized discovery layer is a concise summary rather than a full translation of the article; practical, halakhic, medical, legal, historical, mystical or empirical claims remain source-framed and subject to the canonical review status.