The essence of love and compassion is understanding, the ability to recognize the physical, material, and psychological suffering of others, to put ourselves "inside the skin" of the other. We "go inside" their body, feelings, and mental formations, and witness for ourselves their suffering. Shallow observation as an outsider is not enough to see their suffering. We must become one with the object of our observation. When we are in contact with another's suffering, a feeling of compassion is born in us. Compassion means, literally, "to suffer with."

When we want to understand something, we cannot just stand outside and observe it. We have to enter deeply into it and be one with it in order to really understand. If we want to understand a person, we have to feel his feelings, suffer his sufferings, and enjoy his joy. The word "comprehend" is made up of the Latin roots, cum, which means "with," and prehendere, which means "to grasp it or pick it up." To comprehend something means to pick it up and be one with it. There is no other way to understand something. In Buddhism, we call this kind of understanding "non-duality." Not two.