To set an example is to behave in a way you want other people to copy. The older child who says please without being asked.
It takes for or to: set an example for the little ones. Setting a good one is the ordinary use, but the phrase also runs the other way — make an example of somebody means punish them publicly so that others take note, which is the same idea with the kindness removed. Lead by example is what you say about a manager who does the work as well as allocating it.
1phraseset an exampleTo behave in a way others should copy.
“Older children set an example for the little ones.”
set an example is a model for others to copy.
Practised in Common Word Pairs