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
Appetite comes with eating.
~ Seven babysitters make the kid to lose an eye.
You can't help grief with tears.
Live for a century, learn for a century, but die being a fool anyway.
Who is talking about what, and a lousy one about the bath.
You see your friends in the times of trouble.
Better late than never.
One in the field is not a warrior.