Contemporary American Reform Responsa ( New York, 1987), ♯4
QUESTION: A lawyer has discovered that a fellow attorney is providing a client with advice which will lead to an illegal act and the possibility of considerable financial loss. The lawyer asking the question has gained this information in a confidential relationship. Should he break that confidence and inform the client in question?
ANSWER: It is clear that privacy and information gained as part of a professional relationship can generally not be divulged ( Lev. 19.16 Yad Hil. Deot 7), yet this prohibition is not absolute. For example, if knowledge of certain medical information might change a marriage, such information should be presented ( Israel Kagan , Hofetz Haym, Hil. Rekhilut 9). The decision is based upon the principal of the "need to know." Such facts must not be given lightly or simply to complete existing information or for any personal gain. If such information would lead to the protection of lives or prevent personal injury and financial loss, it must be divulged in accordance with the Biblical injunction of Leviticus, "You shall not stand idly by the blood of your neighbor" ( Lev. 19.16). If an individual's life is endangered, immediate action to remove that danger must be undertaken. This was also the interpretation provided for our verse by tradition ( San. 73b; Yad Hil. Rotzeah 1.13 f, 15; 4.16; Hil. San. 2.4, 5, 12; Shulhan Arukh, Hoshen Mishpat 425.10, 426.1). Maimonides considered it necessary to move in this direction in cases of idolatry ( Yad Hil. A. Z. 5.4) and rape ( Yad Hil. Naarah 3.1). This would apply, however, only if the client's life is endangered; that is not the case here.
Maimonides and some others go further through the exegesis of anothe r verse from Leviticus (19.14), "Thou shalt not place a