With accent marks:
Долг платежо́м кра́сен.
The beauty of a debt is its payment
This proverb reminds us that we should always pay our debts back.
The word красен here comes from красный (red). In the old times, красный meant красивый.
The closest English equivalent is "One good turn deserves another".
Other Russian proverbs
Measure seven times, cut one.
Don't bring your set of rules in a foreign monastery
When I eat I am deaf and mute.
Silent means consent.
Time for business, an hour for fun.
An old friend is better than two new ones.
Forewarned is forearmed.
You are greeted by your clothes but bid farewell by your mind.