Be wise

I have noticed today that in French, when we want to tell a kid to be good, the word we use translates directly into "be wise" ("sois sage").
How interesting, that we expect a kid to be wise.
What does it actually mean?
Wisdom is a feature we typically expect to get with age. The "wise man/woman" is rarely pictured as a 20 year old... Let alone a 3 year old...
The encyclopedia Britannica tells us that wise means "characterized by wisdom : marked by deep understanding, keen discernment, and a capacity for sound judgment". Knowledge, insight, judgment. Can a kid have that?
Sometimes I feel like yes, they can. They can have a deeper sense of wisdom than many adults sometimes. Do they remember stuff we have forgotten throughout our years of conditioning?
I am wondering at the moment how I would be around my kids if I had any.
I look at my nephews and their parents, and really wonder how I would do things.
The more I look at it, the less judgment I have on how my brother and his wife are doing things.
Parents do the best they can, really.
And let's face it, our kids will probably need therapy anyway, no matter what we do...