With accent marks:
На Бо́га наде́йся, а сам не плоша́й.
Put your trust in God, but don't make mistakes yourself
This Russian proverb is a close equivalent of the English expression "God help those who help themselves".
"Не плошай" means "do not make mistakes", it is an obsolete word and can only be seen in proverbs or books.
Other Russian proverbs
What goes around comes around.
Hurry to much and you will make people laugh.
Do not chop the branch you sit on
Strike the iron while it's hot.
There are no friends for taste and color.
You see your friends in the times of trouble.
In a healthy body, healthy mind.
One head is good, but two ones are better.