Mercifulness

Reflecting on dreams, I realize that mercifulness is more difficult than it seems. I wish I could teach it with a short story that would reach the four corners of the world.
I ache to see so many have no food, no safety, no justice. I believe human beings have to change this. There is goodness for who sees it.

It would be hard to live in certain countries and to be a thinker or a dreamer.
Mercifulness, how to teach this?