In O. Henry's "The Gift of the Magi," the third-person narrator suggests that sacrifice equals love, which equals wisdom. He sums up the theme of the story in the last paragraph:
"And here I have told you the story of two children who were not wise. Each sold the most valuable thing he owned in order to buy a gift for the other. But let me speak a last word to the wise of these days: Of all who give gifts, these two were the most wise. Of all who give and receive gifts, such as they are the most wise. Everywhere they are the wise ones. They are the magi."
In this story, Della has her hair cut so it can be sold and she can have money to buy her husband, Jim, a Christmas present, a chain for his watch, his prized possession. Ironically, Jim sells his watch so he can have enough money to buy his wife, Della, a set of combs for her long hair, her prized possession.
The reader might be tempted to look at the actions of the two as something silly, and, in fact, the narrator calls their actions, "not wise." In addition, Della's reactions throughout the story suggest a certain childishness. She decided "There was nothing to do but fall on the bed and cry" when discovering she didn't have enough money for a gift. She creates an over-importance in buying her husband a gift that would demonstrate "Something almost worth the honor of belonging to Jim."
However, the narrator makes it clear that both Della's and Jim's actions are symbolic of sacrifice that is necessary when it comes to love. His comparison of their actions to the gifts of the Magi at the birth of Christ demonstrates the importance of their sacrifices.