“Question: Is it ok to do a hefsek tahara after lighting Shabbos candles?
Introduction: Hefsek tahara is the bedika performed by a niddah prior to beginning shivoh nekiyim. It is ideally performed later in the day close to bein hashmoshos (Shulchan Aruch Yoreh De’ah Siman 196 se’if 1), and must be performed before shki’ah to enable her to begin shivoh nekiyim. Except for the first day of bleeding, the bedika can be performed at any time of the day, and even in the morning. If a lady is performing hefsek tahara on the first day of bleeding (which is an unusual situation) the hefsek must be performed later in the day, close to bein hashmoshos (Shulchan Aruch ibid se’if 2).
According to the Remo (Yoreh De’ah Siman 196 se’if 11) hefsek tahara can only be performed on the fifth day following the onset of bleeding. This means if a period began any time on Sunday (whether motzo’ei Shabbos or Sunday afternoon) hefsek tahara can only be performed on Thursday, which is the fifth day from the beginning of the bleeding.
Ideally a lady should wash herself before performing a hefesek tahara (Remo Siman 196 se’if 3). This washing is not essential and a lady should certainly not delay hefsek tahara because she is not able to wash herself first. On Shabbos and Yom Tov the washing should also be performed, taking care not to contravene any Shabbos and Yom Tov prohibitions.
Discussion: The Remo (Yoreh De’ah Siman 196 se’if 1) brings conflicting opinions about performing hefsek tahara after the tzibbur have davened Ma’ariv early on Erev Shabbos; the first opinion maintains that hefsek tahara can no longer be performed, and the second opinion maintains that it is still permitted to perform hefsek tahara (while it is still day). The conclusion of the Remo himself is that the minhag is to be strict ideally, but ex post facto hefsek tahara can still be performed after the tzibbur have davened Ma’ariv on Erev Shabbos. No mention is made in the Remo about the personal kabbolas Shabbos of this lady (through candle lighting or davening Ma’ariv).
The Shach (ibid s.k. 4) infers from various sources that even if this particular lady has also davened Ma’ariv and been mekabel Shabbos early (as well as the tzibbur), it is still permitted for her to perform hefsek tahara (while it is still day). However, the Shach quotes from his father and from the Maharshal, that if both the tzibbur and this particular lady have davened Ma’ariv, she may no longer perform hefsek tahara. (The position of the Shach himself in this scenario remains ambiguous.)
The Beis Lechem Yehudah (quoted on se’if 1) infers from the words of the Shach later in the Siman (s.k. 19) that the Shach himself understands the Remo unlike his father; namely, that even in a situation where both the tzibbur and this particular lady have davened Ma’ariv, she may still perform a hefsek tahara.
The accepted halacha is to follow this opinion, and even if both the tzibbur and this particular lady have davened Ma’ariv and been mekabel Shabbos she may still perform a hefsek tahara (Aruch Hashulchan Yoreh De’ah Siman 196 se’if 21; Rav Ezriel Aurbach in Levushei Oz Siman 196 se’if 1; Rav Binyomin Forst in Halachos of Niddah volume 2, chapter 30).
Conclusion: Although ideally a lady should ensure to perform hefsek tahara before being mekabel Shabbos; if for whatever reason she has already been mekabel Shabbos and has not yet performed a hefsek tahara she may still perform hefsek tahara as long as it is still day (i.e. before shki’ah).
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