Responsa על בבא בתרא 61:8

a) Q. A was a Gabbai (officer) of a cemetery for twelve years. He lent two marks to the charity chest of the cemetery. When he took an oath as to his wealth from which he was to pay taxes, he included among his assets the two marks due him from the charity chest, and paid taxes for the whole amount. Subsequently he resigned his post as Gabbai and demanded that the community order the new Gabbai to pay him the two marks. When the case appeared at court, A said to the community representatives: "I do not ask anything from you." The judges construed this statement to mean that A relinquished his claim, in spite of A's protests that he meant to say that he demanded the money from the charity chest and not from the community.
A. It is customary for charity officers to advance their own money when the charity chest is empty and to collect it afterwards. Such officers' claims that money is due them from the chest are believed. Therefore, A is entitled to collect his two marks, and his subsequent explanation of his statement "I do not ask anything of you", should be accepted.
b) Q. Some members of the community are ready to testify in A's behalf. Is their testimony admissible as evidence?
A. The testimony of residents of a city is admitted as evidence in a case to which all the residents of the city are a party, if their testimony is against the interests of the city residents. Such testimony, however, is not admissible against the relatives of the witnesses.
SOURCES: Pr. 1012; Mordecai Hagadol, p. 301a; ibid. p. 350a; cf. Mord. B. B. 489; Weil, Responsa 124.