Very quickly review the גמרא דף יח. “ולמאן דאמר פרצוף (seventh line of the Amud) until the two dots.
Learn the גמרא דף יח: “תנו רבנן (two dots) until “ואמר ר’ ירמיה (eight lines before the medium size lines)
The Gemara earlier listed two explanations of the ויבן. See גמרא נדה דף מה עמוד ב for a different explanation that Hashem gave women בינה יתירה
Questions:
Why is it prohibited to walk behind a lady?
See רש”י ברכות דף סא. “אפ’ היא אשתו
See באר היטב אבן העזר ס’ כ”א ס”ק ב & פתחי תשובה ס”ק א who quotes the שו”ת רדב”ז חלק ב ס’ תש”ע which explains the reason it is prohibited to walk behind a lady is because it could cause the man to have inappropriate thoughts about her.
Would this be an issue by Adam according to the opinion of דו פרצופים ?
Does Rashi agree to the רדב”ז?
In the halacha that one may not walk behind a lady when crossing a body of water
Why did רש”י דף יח: “בנהר say it is referring to a married women?
Learn מהרש”א ברכות דף סא. “ואפילו היא אשתו who answers all the above questions
Is there a prohibition to have inappropriate thoughts about a single girl?
Learn שולחן ארוך או”ח ס’ רי”ז סע” ד with משנה ברורה
What should a person do when walking in sidewalk or in market with so many people where it’s difficult to avoid walking behind a lady?
See שו”ת ציץ אליעזר חלק ט ס’ נ
Why is it worse to walk behind a עבודת כוכבים
What is the major issue of walking behind a shul during davening?
Learn מהרש”א ברכות דף סא. “אחורי ארי
What’s the halacha regarding walking by a shul when they are in middle of davening?
Learn תוס’ “ולא אחורי
Learn שולחן ארוך או”ח ס’ צ סע’ ח with משנה ברורה