With accent marks:
Терпи́, каза́к – атама́ном ста́нешь!
Be patient, Cossack - you will become an ataman!
This expression is often used in a joking manner to encourage a person to patiently endure difficulties.
The expression itself is a catch phrase from the Gogol's novel "Taras Bulba". When the Cossack army surrounded the city of Dubno and a long siege began, one young Cossack got bored, and Taras said to him: "Be patient, Cossack - you will become an ataman!" Ataman is a Cossack leader.
Other Russian proverbs
Each sandpiper praises its swamp.
Crowded, but not aggrieved.
Free cheese is only in a mousetrap.
It is not a place that makes a person look good, but a person that makes a place look good.
If I knew where I would fall, I would lay some straw there.
Being a guest is good, but being at home is better.
Make a fool pray to God - he will break his forehead.
Get your sleigh ready in summer and your (horse-drawn) cart in winter.