Having empathy for others is something we start to learn from a very young age.
Sometimes it takes a little while for the lesson to sink. Most parents, whether they have other kids or not, find ways to bring these lessons into their child's life, but having a younger sister was a really formative experience for me. Having a sibling taught me really quickly to think beyond myself and about others' needs.
Naomi and Peter are twin siblings who were recently playing when their parents caught something amazing on video that we can all learn from.
They were in the middle of playing when Peter became upset and sat down on the floor. Naomi followed, sitting right next to him.
Once she realizes something is wrong, she reaches out to hug and kiss him to make him feel better.