Proverbs were a favourite motif for seventeenth-century illustrators. In this painting, the young girl shows her mother ‘the rotten apple that spoils all the rest’ (‘een rotte appel in de mand, maakt al het gave fruit te schand’), which informs us that evil is infectious, and that good morals can be corrupted by bad company. The poet and moralist Jacob Cats describes this proverb in his book Spiegel van den ouden ende nieuwen tijd (i.e. ‘Mirror of the old and new times’; 1632), specifically reminding parents that a child’s tender soul is very susceptible to bad influences.