Much of life is monotonous.  We have routines and schedules that seem to be much the same over and over and over.  However, there are those moments that break the trend.  Moments in our lives where we've undoubtedly been in the presence of God.  A time where we had an encounter.  Those times need to be remembered.  They need to be memorialized.  When life gets hard, or when we face a season of drought, it is good to remember, to go back to these spiritual markers.