As it
says".....On the heal of humility comes fear
of Hashem."
Humility is based on realising the
greatness of the creator.We are less than a speck
of dust compared to even one small part of
creation.In His Kingdom we must act small among
the smallest.The more one realises how
insignificant he is the more humble he
becomes.The more humble one becomes the more he
will fear to do anything which is against
Hashem's will.(Malbim)