If we are all part of a larger system, call it humanity or consciousness, helping each other out is helping ourselves. If we can better put see and feel the world through another persons eyes- that means our ability to help us that person(s) is much better because we understand the issues with more info, and more info is almost always better. It does not mean we need to make the feelings felt through empathy our own or have to do anything about the them, if they come in direct conflict of our own singular needs. The feelings of empathy may move you to act in a different way but your agency is still your own.