With accent marks:
Под лежа́чий ка́мень вода́ не течёт.
Water does not flow under a lying stone.
In this proverb, the "lying stone" symbolizes a person who does not want to do anything. If nothing is done, things will not budge, nothing will change.
The proverb is usually used to talk about someone who does not take care of himself, does not want to change anything in his life, and expects someone to help him. As a result, the whole life can pass by and the person will not achieve anything.
With such a proverb, we encourage this person to action.
A close equivalent in English is "No song, no supper".
Other Russian proverbs
Water wears away a stone.
Start taking care of the dress while it's new, and of your honor while you are young.
You can't command to the heart.
Strike the iron while it's hot.
Patience and labor will grind everything.
You are greeted by your clothes but bid farewell by your mind.
The one who walks will go through.
Fear has big eyes.