Esau had the potential for greatness... he was meant to be the father of six of the tribes. Isaac saw great potential in Esau and wanted to give him the spiritual leadership blessing. Esau lamented terribly when he did not receive the blessing from Isaac, from his great desire to fulfill that important, lofty position. The Lev Eliyahu says that if we saw Esau today he might look and dress like an upright Jew. Bereishit Rabbah says that Esau tried to make himself appear very pious. Since Isaac married at age forty, Esau did the same. But there were flaws in Esau that were spiritually significant. Before Esau married he engaged in all sorts of sexual immorality. And when he did marry, he married Hittite women. The women grieved Isaac and Rebecca because they worshipped idols, and the Shechina (Divine Presence) departed from their home.