When Moses sees the burning bush, God tells him: Come no closer here. Take off your sandals from your feet, for the place you are standing on is holy ground…Yet later on, at Sinai, we read: the people stood at a distance, and Moses drew near the thick cloud where God was.  Ramban points out that even though Moshe was the greatest person to live, his greatness did not come at once but developed over stages. If this was true for Moses, how much more so for us, we cannot expect spiritual success to come all at once, rather it must be allowed to develop over time.