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
You can't help grief with tears.
Do not chop the branch you sit on
Who is talking about what, and a lousy one about the bath.
The morning is wiser than the evening.
You can't hide an awl in a bag.
Silent means consent.
Do not dig a hole for another one, you will fall into it yourself.
There are no friends for taste and color.