Hi, it means "be at peace", but as an imperative, more like "stay quiet".
![Smiley :)](https://www.kymcoforum.com/Smileys/default/smiley.gif)
In Croatia you'd say that to a restless child, for example.
However, if your friend is Macedonian, the language is quite different than mine, so it can have somewhat different meaning.
![Grin ;D](https://www.kymcoforum.com/Smileys/default/grin.gif)