Wellspring means source i.e the extreme source or simply put, the only basic source of all that has happened, happening and will happen to you. 

A dirty source can’t produce anything clean. A heart full of bitterness and anger can’t produce joy and forgiveness. A poor heart can’t produce riches and wealth. 

Let the word of God be your soap and confessing Gods promises be the water you use to clean your heart so that it can produce riches and wealth for you.