Hazrat Ali said

O son of Adam! By not being happy with wealth, and not being disappointed by poverty.

And do not be saddened by adversity, and do not fall into arrogance from happiness. Because gold is consumed by fire, so is a good servant tested by suffering - and you cannot get what you want without giving up your desires. And cannot fulfill his hopes without being patient with things. And do your utmost to fulfill the duties entrusted to you, and be content with what Allah has decreed for you.

A good servant is tested by adversity.