Everybody thinks that compassion is important, and everyone has compassion. True enough, but the Buddha gave uncommon quintessential instructions when he taught the methods for cultivating compassion, and the differences are extraordinarily important.
Generally, everyone feels compassion, but the compassion is flawed. In what way? We measure it out. For instance, some feel compassion for human beings but not for animals and other types of sentient beings. Others feel compassion for animals and some other types of sentient beings but not for humans. Others, who feel compassion for human beings, feel compassion for the human beings of their own country but not for the human beings of other countries. Then, some feel compassion for their friends but not for anyone else. Thus, it seems that we draw a line somewhere. We feel compassion for those on one side of the line but not for those on the other side of the line. We feel compassion for one group but not for another. That is where our compassion is flawed. What did the Buddha say about that? It is not necessary to draw that line. Nor is it suitable. Everyone wants compassion, and we can extend our compassion to everyone.
-- from Lectures on Kamalashila's 'Stages of Meditation in the Middle Way School' by Kenchen Thrangu Rinpoche, translated by Jules B. Levinson