This
database is a comprehensive collection of all the American idioms and slang available.
American Idioms are many and varied. We hope you enjoy our collection. We are adding more all the time.
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you cannot justify doing something wrong or bad just because somebody else has done the same thing to you
Two wrongs don't make a right and just because the boy's friend was not punished for taking the equipment without permission, this did not make it right for others to do the same thing.
If someone preaches to the choir, they talking about a subject or issue with which their audience already agrees.
('Preaching to the converted' is an alternative form.)