To open deeply, as genuine spiritual life requires, we need tremendous courage and strength, a kind of warrior spirit. But the place for this warrior strength is in the heart.To my mind, the best way to cultivate the warrior strength of the heart is to practice tonglen - a compassion practice in which we share another's suffering on a spiritual plane. Practicing tonglen keeps us from closing down our heart and it brings us to a deep empathy. Interestingly, it also helps us with our own suffering. Most people report that doing tonglen reliably helps them feel better - no matter what kind of pain they're experiencing. Of course, it's not necessary to be in pain to practice tonglen. We can do it any time and any place. As Pema Chödrön says:
The tonglen practice is a method for connecting with suffering —ours and that which is all around us— everywhere we go. It is a method for overcoming fear of suffering and for dissolving the tightness of our heart. Primarily it is a method for awakening the compassion that is inherent in all of us, no matter how cruel or cold we might seem to be.