Our own kind heart alone does not help. It does not help just to keep our kind thoughts inside our chests: we need to show them. Loving-kindness and compassion are about actually bringing benefit to other people. If we think that love and compassion are precious and valuable, like valuable jewels, and that we need to keep them for ourselves, then this is not really loving-kindness and compassion. Our love and compassion should be like radiating lights, and they should radiate as much as possible to help other beings.

How can we practice so that they do radiate? How can we make others happy? How can we help others? We should not merely have the loving and compassionate wish that others be happy and free of suffering. We should free them from suffering and make them happy. We should express love and compassion through our body and speech so that other people actually experience the results of our actions. Otherwise, loving-kindness and compassion are nothing special.

~ 17th Gyalwang Karmapa's Teachings: The Fivefold Mahamudra / 2007.12.19

http://the17thkarmapa.blogspot.sg/2012/07/17th-gyalwang-karmapas-teachings.html