"How deeply you touch another life is how rich your life is." - Sadhguru
The whole process of yoga is to give yourself. It is possible to simply sit, close your eyes and give yourself to the world. But that level of awareness is not there in most human beings. Without activity, most people may not know how to give themselves. They need action to give themselves to something. Volunteering is a tremendous possibility in that direction – you can offer yourself through your work.