"and you shall not take as a pledge the garment of a widow": whether poor or rich. And even (if she were as rich) as Marta b. Baithus.
R. Shimon says: The things that you take as a pledge and return (at given times), you may not take from a widow, so that you not frequent her house and impute a bad name to her.
(Devarim 24:19) "When you reap your harvest in the field, if you forget a sheaf in the field, do not return to take it": to exclude its being reaped by robbers, ravaged by ants, or broken by the wind or by beasts.