The merit of Tzedaka is so great that I am happy to give to 100 beggars even if only one might actually be needy. Some people, however, act as if they are exempt from giving charity to 100 beggars if one of them might be a fraud.(The Sanzer Rebbe)
“I appeared to Abraham, to Isaac, and to Jacob…” (Exodus 6:3). This seems to be a very straightforward and unambiguous statement by God to Moses.