Once, I was sitting directly opposite my grandparent and grandson on the subway line 2. Look closely, the little boy's face is not very good, Grandma is holding a medicine bag in her hand, it seems that they have just been to the hospital. The grandmother raised her hand and put it gently on her grandson's forehead. "Oh, it's still burning," she said with a smile. "I'll take my medicine after dinner." Blinking his big eyes, the little boy replied, "Well, it still seems to be burning. But grandmother, how did you know I wasn't well?" Seeing this, I immediately imagined several responses my grandmother might give, such as, "You get to know when you're old," or "Of course Grandma knows." My hasty guess turned out to be completely off the mark. "Well, sicker people find sick people," she said, smoothing her little grandson's messy bangs. People who have been injured always know better the depth, width and pain of the wound. So when someone else sees a similar scar on their body or heart, the injured person is more likely to empathize with it. Those scars in the heart gave them a pair of eyes to see the world's suffering. Maybe that's what grandma wants to tell her grandson.