With accent marks:
Куй желе́зо, пока́ горячо́.
Strike the iron while it's hot.
This proverb came from blacksmithing. A blacksmith intentionally heats a piece of iron in the fire so that it becomes softer, and until it cools down, he hits it with a hammer, giving it the desired shape. When the iron is cooled, it is no longer suitable for work.
This proverb emphasizes that everything must be done on time. And if you missed a moment, if you did not take your opportunity on time, then probably later it will be impossible to do.
Other Russian proverbs
An old friend is better than two new ones.
Do not dig a hole for another one, you will fall into it yourself.
Don't go to the woods if afraid of wolves.
Time for business, an hour for fun.
A bad example is contagious.
If you are chasing two hares at once, you won’t catch a single one.
A bird is visible by its flight.
Live for a century, learn for a century, but die being a fool anyway.