QUESTION: May a berit milah be conducted at twilight or at night? (Mark Lebovitz, Cherry Hill NJ)
ANSWER: The stipulation that circumcision must take place during the day, on the eighth day, rests on a Biblical foundation (Gen 17.12; Lev 12.3). The Talmudic discussion was first concerned with how early it might be possible to circumcise. The Mishnah stated that the sun should have risen but if the circumcision or other matters there discussed were performed after dawn it would be acceptable (M Meg 2.4; 20a ff3. It was always considered preferable to have the berit early in the day in order to display eagerness to perform the commandment just as Abraham had been eager to obey God (Gen 17.12; Kid 29a). There was general agreement that circumcision may not take place at night and that circumcision must occur on the eighth day unless postponed for health reasons. There was some Talmudic discussion about evening circumcision when the berit had been postponed. Despite a lengthy debate which hinged upon the interpretation of a Biblical verse (Lev 12.3), the final decision was for daytime circumcisions (Yeb 72b; Kid 29a; Meg 20a ff; Shab 132b ff). We should note that during the Talmudic period, when some of these matters were still in flux, one authority, R. Papa, felt that no circumcision should occur on a cloudy day or during bad weather. This injunction may have been made to guard the infant's health. The Talmud indicated that it was not to be followed (Yeb 72a).
All of the later authorities agreed that circumcision may occur only during the daytime. Solomon ben Aderet wrote a responsum on this specific question and came to the same conclusion (Responsa I #877). This subsequently was also the decision of Maimonides (Yad Hil Milah 1.8) and Joseph Caro (Shulhan Arukh Yoreh Deah 262.1). Later authorities agreed with it (Sheelat Yaabetz I #35).
The Mishnah and the Talmud discussed the whole issue of twilight in connection with the specific time for various commandments (Meg 20b ff; Yeb 72b; Shab 137a ff; etc). For circumcision this discussion was principally connected with shabbat. In other words should a child born during twilight, eight days earlier or whose head emerged at that time, be circumcised on shabbat? The definition of twilight was not clearly provided; for some it was the period after the sun had set but daylight remained. For others it was a period of fifteen or twenty minutes before three stars were visible (Yad Hil Milah 1.12 and commentaries, Shulhan Arukh Yoreh Deah 262.4 ff and commentaries; B. Auerbach Berit Abraham page 126 ff).
If the circumcision occurred at night, and twilight was generally considered as night, then it was obligatory to take at least a drop of blood during the next day according to some (Solomon ben Aderet Ibid; Shulhan Arukh Yoreh Deah 262.2). There were, however, early authorities who indicated that no drop of blood needed to be taken (Rabenu Asher as quoted by Bayit Hadash to Tur Yoreh Deah 262), while the custom of taking a drop of blood seems to have originated in the Hagahot Maimuni.
We conclude that a berit milah should not take place at twilight under normal circumstances. If it nevertheless occurred; we would consider the berit valid as did our forefathers and would not require a tipat dam.
The specific time frame for each of the mitzvot including berit milah has been specified in the Talmudic tradition and has usually been derived from a specific Biblical verse without any other reason. We do not, for example, know specific logical reasons for the long list of religious rituals to be performed during the daylight or at night, given at the end of the second chapter of Mishnah Megilah (see also Meg 20b). We should follow the tradition in these matters as there is no compelling reason to change it.