Rav Judah said in Rav's name that when God told Abram in , "Walk before me and be perfect," Abram was seized with trembling, thinking that perhaps there was some shameful flaw in him that needed correcting. But when God added in , "And I will make My covenant between me and you," God set Abram's mind at ease. Rabbi Hoshaiah taught that if one perfects oneself, then good fortune will follow, for says, "Walk before me and be perfect," and shortly thereafter reports Abram's reward for doing so: "And you shall be a father of many nations."