If you are invited to a Shabbos luncheon in Boro Park and the food being served had been carried from a house to the shul on Shabbos. The host Rebbe told him he could use the Eruv in Boro Park but your Rabbi told you that under no circumstances may you use the Eruv as per the ruling of Rav Moshe Feinstein.
Are there certain times we can be lenient in regards to מעשה שבת ?
Learn משנה ברורה ס’ שי”ח ס”ק ב
Why is this so?
See קובץ תשובות ח”ב כ”ד who asks on the Mishna Berura from the halacha in שו”ע ס’ שכ”ה סע’ ז fruit which there is a uncertainty if a gentile cut them off the tree on shabbos or prior may not be eaten on Shabbos? See Rav Elyashuv answer
See ארחות שבת ח”ג פרק כה סע’ לה
and אגרות משה או”ח ח”ד ס’ קיט אות ה
Is the carrying considered a מתעסק and is that more lenient than a מעשה שבת done בשוגג?
See ארחות שבת ח”ג פרק כה סע’ ד
See שמירת שבת כהלכתו פרק י הערה מד
What is the Halacha if someone carries a key to open a door of a shul or house, may one enter the shul / house?
Can one drink milk that was milked and processed on Shabbos by a plant that is owned by a Jew?
We learnt the מגן אברהם ס’ שי”ח ס”ק לא who discusses what the halacha is if someone intentionally cooks on Shabbos for a specific person? Can the person eat the food after Shabbos?
What is the proof of the Pri Megadim from our Gemara שבת דף לח that there is no difference between the ruling of מעשה שבת between an איסור דאורייתא & דרבנן ?
Clarify the answer of the ביאור הלכה why there is no proof from our Gemara.
Does the משנה ברורה / ביאור הלכה rule like ר’ מאיר when someone violates Shabbos במזיד by an איסור דרבנן?