through criminal activity or considerable financial loss, must be presented. This is based on a Biblical statement ( Lev. 19.16) as well as later authorities ( Yad Hil. Rotzeah 1.13; Shulhan Arukh Hoshen Mishpat 426.1; Elijah of Vilna Biur Hagra, Hoshen Mishpat 425.20; Isserles to Shulhan Arukh Hoshen Mishpat 388.11). Furthermore, in a criminal case every witness is obligated to testify if he possesses personal knowledge of the events ( Lev. 5.1; B. K. 55b; Isserles to Shulhan Arukh Hoshen Mishpat 28.1).
It is also clear that a person is obligated to testify before a Jewish or non-Jewish court in order to save himself from threatened punishment. Under such circumstances, one is moser beones ( Tur Hoshen Mishpat388; Shulhan Arukh Hoshen Mishpat 388.8ff; Yad Hil. Hovel 8.2). We should note that there is no problem of testifying before a non Jewish court. We have records of a Jewish community handing a Jewish criminal who had injured a non- Jew to a gentile court as early as the Gaonic Period (700-1000 C.E.; J. Mueller, Mafteah, p. 182).
It is quite clear, therefore, that Jewish law requires an individual to testify and that there is no reason to hesitate.
Reform Responsa for Our Time ( Cincinnati, 1977), #6
Solomon B. Freehof
QUESTION: May information obtained through electronic eavesdropping be used as evidence in Jewish law? (Asked by Rabbi Richard E. Steinbrink, Saint Louis, Missouri)
ANSWER: Jewish law is basically religious (canon) law, and therefore it is not surprising that many of its rules are widely different