英語のことわざ

Spare the rod and spoil the child.

This proverb is for parents. It says that if you are not strict with your children, punishing them when they have done something wrong, they will grow up spoilt and over-indulged. "The rod" means the stick that used to be used to beat children when they did something wrong. As a punishment, this may sound a little extreme now, but here "rod" is used as a metaphor for strict discipline.