Behrman needed to paint a masterpiece. He had lived his life waiting for the right moment. When Johnsy needed a will to live, Behrman gave his life for Johnsy. This story is unique in that Behrman was willing to lay down his life for a friend. There is no greater love than that (John 15:13).
Johnsy had given up on life until she realized that she had been thinking only of herself. Behrman gave everything he had for his friend. That is unique love. In fact, John 15:13 says there is no greater love than to give your life for your friends. Behrman paid the ultimate sacrifice. He stood in the icy cold all night in order to give Johnsy hope to hang on to life. While painting the last leaf, he developed pneumonia. He died because of his love for his friend.
This type love can be compared to Christ's love at the Crucifixon. That is what makes this story unique. It is composed of a love that many people do not possess. In the end, Behrman gets his masterpiece while trying to give Johnsy a will to live. The price Behrman paid was his life. That is unique love. Behrman was trying to save his friend.