What is an example of an allusion?

An example of allusion is the phrase “good Samaritan” (a compassionate person) which we often come across in everyday speech. For instance, “After I fell off the bike, a good Samaritan passing by stopped and called for help.”

This is an allusion to the parable of the good Samaritan from the Bible, in which a Samaritan helps a beaten and robbed traveler while others pass by. We use the phrase to signify an act of kindness from an unexpected source.