There are days when we have experiences which make us feel that it is better to close our hearts. However, all the great wisdom traditions encourage us towards a softening of the heart, toward a warm opening to others, even when that seems to be dangerous. As humans, a huge portion of our energy each day is spent dealing with anxiety and the fear of losing safety. These can arise suddenly and take all our attention, encouraging us to close, to become cool, to harden around ourselves. In Buddhism, one antidote to this is to cultivate an opening toward others in “Metta” or Loving-kindness practice. Metta has the connotations of “spreading” or “expanding”. It is radiant. It reaches out. It is an active friendliness  in interpersonal relationships which we cultivate. It works against the fears which  make our lives narrow and dark, and the tendency to dualistically split our lives into “me” and “them”

As a mother at the  risk of her own life protect her child, her only child, even so should one cultivate a limitless heart with regard to all beings. So with a heart of boundless friendliness  should one cherish all living beings; radiating kindness over the entire world.

The Buddha, Sutta Nipata I, 8 b – The Metta Sutta.