This Is A Well Known Saying, Book, Play, Proverb Or Phrase

[pigswillfly]

It that has something to do with numbers and the clue is:
T is always S I N
Has anyone got any ideas what it is?

Thanks!

[Buenchico]

There is always safety in numbers

[jno]

I expect Buenchico is right; but I've never heard it with the word "always" in it.