Nothing great happens suddenly. Not even a fig.

Where this comes from

A man asked Epictetus how to get his angry brother to make up with him. That part is up to your brother, Epictetus said. What you can work on is yourself, and that takes time. Nothing great happens suddenly, not even a fig: first the tree flowers, then the fruit grows, then it ripens. His student wrote it down about 1,900 years ago.

How you could say it to a five-year-old

“Your bean didn’t sprout overnight? Figs don’t either. Let’s look again tomorrow.”

Epictetus, Discourses 1.15. We put these lines into plain English ourselves, staying close to the original and to public-domain translations.