One of my favorite analogies of faith is that of a human muscle. 

Without regular exercise and use, muscles atrophy. They slowly deteriorate until they are unable to perform when needed.

To get the most out of them, they must be developed.  Proper development comes two ways.  The first way is through repeated use.  Take the time to use your muscles through regular exercise.  The second way is to use resistance.  Weight training is the use of artificially heavy objects to develop stronger muscles. For example, you pick the barbell up and down to gain strength.

Faith is developed in much the same ways.  You need to be regularly using it in some way through prayer or service.  Ask God to show up and see what he does.  Use what you know in some new and scary way and see how God makes it work out.

The other way to increase faith is to meet resistance.  This can be stepping out into the unknown with only God to catch you.  It can also come from walking through difficult seasons with only your faith to guide you.

Muscle development is not easy.  It takes dedicated hard work daily to develop a body you are proud to show off to others. 

Faith is even more difficult.  It takes a completely committed Christian surrendering their will to God daily to develop a faith that will shine a light to others. 

Faith is a muscle.  The follow-up question is, “Are you a weak or a strong person?”