On the train ride, Montag is trying to memorize Matthew 6:28, which instructs readers to forget about material possessions and to "consider the lilies of the field," beautiful blooms that grow wild on their own. His antagonist is an advertisement for Denham's dentifrice. The jingle in the ad is so abnoxious and incessant that it invades his thoughts and keeps him from being able to focus on anything meaningful.
