Faith

Now Faith is the substance of things hoped for, the evidence of things not seen

Most of the time when we think of Faith, we believe in something that is possible.
Like I have Faith that the sun will come up tomorrow, or that if I take some medicine my headache will go away
It is not faith when you say if I set down, the chair will hold me, this is not the Faith that God is talking about.  He is talking about the Miracle working Faith.  You need Faith to bring you though a deadly decease that have no cure or like the lady with the issue of blood.  She had been to doctor after doctor trying to be cured of her issue.  The doctor had no cure for her.  She went out to fine a cure and she found it in the believe in the healing power of Jesus. It take Faith for the Anointing to work.  Jesus gave his follower some instruction regarding Faith, because of all the unbelief he faced amounge the poeple