Tara Brach writes in Radical Acceptance: Awakening the Love That Heals Fear and Shame Within Us:

To cultivate the tenderness of compassion, we not only stop running away from suffering, we deliberately bring our attention to it. Buddhist compassion practices usually begin with being aware of our own pain because once our hearts are tender and open to our own suffering, we can more easily extend compassion to others. Sometimes we most easily connect with tenderness by first focusing our attention on the suffering of others and then bringing attention to our experience. Either way, as we feel suffering and relate to it with care rather than resistance, we awaken the heart of compassion. As we practice responding to our suffering with the kindness of compassion, our hearts can become as wide as the world.