You don’t look a gift horse in the mouth.
More Mexican Proverbs:
With poison, one drop is enough.Mexican
To the hungry man no bread is bad.
Mexican
Hell must be in bad condition when even the devil stays out.
Mexican
Keep your counsel arrested until it's requested.
Mexican
If you want to live in peace, you must not tell everything that you know, nor judge everything that you see.
Mexican
For every dog there is an appropriate stick.
Mexican