Because you don't have faith.

Jesus can hit the issue pretty hard, and this morning was no different.  There's a story in Matthew 17 that tells of a man coming to Jesus to have him cast out a demon in his son.  Jesus does it with a simple word.  Then the disciples asked why they couldn't do it. 

You see, the disciples had already tried to cast out this demon but were unsuccessful.  Something went wrong to say the least.  Jesus explained that their failure was due to their lack of faith.  Then he says, "if you have faith as small as a mustard seed..." Now a mustard seed is pretty tiny, but I'm not convinced he's actually referring to the size of a mustard seed. 

Think of it this way - what can a mustard seed become when it is planted?  A mustard plant and nothing else!  A mustard seed is never planted hoping to become an apple tree.  It's never planted with hopes of becoming a tall oak.  It always becomes a mustard plant.  True enough the mustard seed is tiny and the plant is fairly large considering these small seedling beginnings. 

I believe that when we have faith like a mustard seed we'll believe who we are and what we are in Christ.  The bible says that we can do all things through Christ.  Do you believe it?  Do you believe that there is anything in this world that you cannot do?  If we have put limits on ourselves and our faith, perhaps we too don't have the mustard seed faith that Jesus is talking about. 

The truth of the matter is Jesus died and rose for you.  Our believing doesn't change that.  He has offered heaven to us, without cost - our believing doesn't change this either.  He says to Peter to walk on water, but Peter sinks.  Peter's faith began to waiver.  He no longer believed like a mustard seed.

Today Lord we pray that you will cast off all doubt and fill us with the faith of a mustard seed.  We believe in you, but help us in the times of our unbelief.  In Jesus' name. AMEN.