Allegory: A story, poem or picture that can be interpreted to reveal a hidden meaning, typically a moral or political one.
In the story "A Very Old Man with Enormous Wings" the allegory here is a moral one. The story shows a couple who housed an angel in cruel conditions, but still saved his life. It shows that although humans are often very cruel, we tend to be kind many times, and often cruelty and kindness go hand in hand when it comes to the treatment of our fellow humans and animals. In the story, the couple that housed the angel were scared of him, because they believed he was there to take their child's life. A theme in many religions is to house everyone, for you never know when they could be a god or an angel. The angel is supposed to be a homeless man, who many find scary, because they don't understand their situation or what they want. Despite thinking the angel was going to take their son's life they housed him anyways, and showed him compassion even if they were afraid, following the moral to house every stranger that is in need.