The Kingdom of God is in the hands of God.  He designed it, created it and he ultimately causes it to grow.  God in the beggining called us to be His stewards.  We are called to spread the seeds of His mission and will.  Like a seed the Kingdom of God begins with something small - one life, a meager faith, a small idea - and put into the hands of God  and by His power and provision it grows to encompass many great things - Mark 4:1-34.