Compassion comes in two parts. The first is the prefix "com" which represents togetherness. The other half is passion. Etymologically, compassion is the understanding that we all have a sense of passion, and it also represents that we all experience suffering. At its core, compassion is the understanding that the suffering of another is valid and of equal importance to your own. You may never know the degree to which someone's angst is experienced, and that isn't your responsibility to know or judge. However, it is your responsibility to understand and to do it with compassion. If you have an abundance where others find struggle, it is common that we can belittle the suffering of others.
In "A Christmas Carol," we understand that Scrooge was privileged to have money whereas Bob Cratchett did not. However, we learned that the Cratchett's were privileged to have family and a loving home, whereas Scrooge did not. For this reason, it becomes a unique social responsibility to utilize one's own blessings and knowledge to alleviate the angst for those in need of it. This changed Scrooge's heart. Consider how the Whos of Whoville responded the morning they awoke to discover their Christmas had been stolen. They began singing. They didn't have presents, and yet they sang. They knew that their joy and abundance was not dependent on items, but on togetherness. This understanding of compassion also helped the Grinch's heart to grow three sizes that day. We are no different.