Lesson Learned?

M comes crying, hurt, to me. I saw what happened, though he's crying his brother's name.
"my nose! It bumped into the rock!"
"did you throw the rock into the air?"
"yeah"
"and it hit you in the nose?"
"yeah"
"what does mommy say about throwing rocks?"
"I'm sorry. I won't do it again."
Then he ran off to mow the lawn.