James 1:4

And let endurance have its perfect result and do a thorough work, so that you may be perfect and completely developed (in your faith), lacking nothing. 

Faith is like a tree that starts small, sending out unseen roots. The tree may look only like a twig, but it is growing and enduring and surviving the storms. Faith becomes stronger as it grows and endures and isn’t shaken when the wind blows or the weather changes. Faith that is planted, watered, and fed by the word is faith that endures.