Little faith is the result of a little amount of God's word in the spirit of a person. If you have little faith, begin to hear more of God's word and your faith will begin to grow.

Mat 6:30 KJV

Wherefore, if God so clothe the grass of the field, which to day is, and to morrow is cast into the oven, shall he not much more clothe you, O ye of little faith (OLIGOPISTOS)?

The Greek word for little faith is OLIGOPISTOS and it means amongst other things; to be lacking in confidence, to trust too little and to be incredulous.

A person with little faith is more concerned about what they shall eat, what they shall put on and the circumstances they face.