According to Cahill, Abraham's encounter with God is that of "a calculating clansman ... self-confident ... who knows how to deal." Abraham wants to know what he will get out of the relationship, this covenant with God. Only when God promises him as many descendants as the stars in the heavens does Abraham "trust in" God. Abraham does this out of "insight," an intuitive leap of faith of the sort a hardheaded businessman would make in assessing the trustworthiness of a potential business partner, and God rewards the trust.
On the other hand, when God speaks to Moses or Moshe, out of the burning bush, telling him to lead his people out of Egypt, Moses responds "with a terror that the patriarchs seldom exhibited." Moses hides his face, afraid to look at God. Instead of challenging God with a "what's in it for me" swagger, Moshe tries to wiggle out of the burden God has laid on him, saying he is not worthy of the task. God tells him it doesn't matter: God will do the heavy lifting.
While Abraham swaggers and Moses cowers, a significant contrast in attitudes, they share important common ground: they both believe their encounter with God is real and they both respond to God's call.