“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,”—Henry David Thoreau.
The mind is like an open field where all kinds of thoughts find their way through to compete. What you allow is what stays. While you cannot control certain words that find their ways into your mind, you can filter them out by dominating your thoughts with positive things alone. Get hold of words that edify, then you can move on to greater things in life.