С миру по нитке — голому рубаха.
Just a thread from everyone in the world, provides a man a shirt.
Literal translation: A thread each in the whole world- a shirt for the naked.

I like this quote. It's very Russian to take a sentimental concept like unity or charity and put it into practical terms. This proverb came up while I was searching for interesting uses for the word нитка-the singular for "thread."

*Please note that in the genitive case you would not say "нитк" but "ниток." A lot of times when there is a genitive for a word with a hard consonant followed by "ка" the letter о will appear and divide the consonant and the к.

Here are some sentences:

Мама, где мои нитки?
Mom, where is all my thread?

Мне нужна красная нитка, пуговица оторвалась.
A button came off, I need the red thread.

Мы все нитки потеряли?! Как я буду шить без ниток?
We lost all the thread?! How am I supposed to sew with no thread?

Держи нитку с иголкой.
Keep the thread with the needle.