As a single footstep will not make a path on the earth, so a single thought will not make a pathway in the mind. To make a deep physical path, we walk again and again. To make a deep mental path, we must think over and over the kind of thoughts we wish to dominate our lives.
This is where we go wrong in a modern age overflowing with information. It’s so easy to enjoy wisdom as a fleeting experience, brief inspiration. Difficult to let it shape a path and solidify a perspective.
One more relevant quote from Thoreau
A truly good book teaches me better than to read it. I must soon lay it down, and commence living on its hint. What I began by reading, I must finish by acting.