If you spend a lot of time with people — talking, drinking, or just hanging out — one of two things will happen. Either you'll become like them, or they'll become like you. Think of it like charcoal. Put a dead piece next to a burning piece. Either the dead one kills the fire, or the burning one lights up the dead one. The risk is huge. So be careful about getting close to ordinary people. Remember: you can't hang around someone covered in soot without getting dirty yourself.
If a man has frequent intercourse with others either for talk, or drinking together, or generally for social purposes, he must either become like them, or change them to his own fashion. For if a man places a piece of quenched charcoal close to a piece that is burning, either the quenched charcoal will quench the other, or the burning charcoal will light that which is quenched. Since then the danger is so great, we must cautiously enter into such intimacies with those of the common sort, and remember that it is impossible that a man can keep company with one who is covered with soot without being partaker of the soot himself.