Could you elaborate on the prohibition of walking behind a woman, and walking between 2 women? What about sitting behind a woman or between 2 women on a bus or airplane?
Answer:
In principle, the Gemara (in Berachos and Eiruvin) writes that a man man not walk behind a woman. According to some authorities (Radvaz) this applies even at a distance, provided that the woman in front is in sight. The reason for this is that walking behind a woman can lead to prohibited thoughts.
Other poskim, however (in the name of the Arizal, and others) write that the prohibition applies only within 4 amos of the woman, and one may be lenient in this matter, if one is confident that this will not lead to forbidden (promiscuous) thoughts.
Some authorities, including Rav Shlomo Zalman Auerbach zt”l, wrote that one can be more lenient today. The reason given by Rav Shlomo Zalman is that it is virtually impossible, in a crowded road, to avoid walking behind a women; if one overtakes one woman, one will find oneself behind another. However, one should be particular about the matter where possible.
Although the Chazon Ish was particular, the prohibition does not appear to apply to sitting behind a woman on the bus or airplane.
One must not pass between two women where there is a “connection” between the women, and walking is clearly an act of coming between them. One should likewise avoid sitting between two women.
However, if there is no connection between the two women on either side, there is room to be lenient under extenuating circumstances, and this can be applied to sitting between two women on an airplane. This should be avoided if possible.
We will bli neder dedicate a full article to this topic, whose parameters and halachic details are not well-known, and which deserves an in-depth analysis.
