When quoting the exact words of an example sentence, a proverb, an email, or the words on a sign, I believe that (per British English) we would place the full stop inside, correct?
The sign read 'Shoplifters will be prosecuted to the fullest extent of the law.'
I didn't like his ungrammatical sentence 'There was too many difficulties.'
His email stated 'The meeting is on December 3rd at the Town Hall. Make sure to bring your lunch, and please be punctual.'
I love the old saying 'A stitch in time saves nine.'
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.