Since parshas Netzavim alludes to the agreed covenant of one Jew being responsible for others, it is an appropriate time to discuss the laws and rules of what we call areivus.
“My father’s yahrzeit falls during the week of sheva brachos for my grandson. May I attend the sheva brachos?”
"My yahrzeit falls on Shabbos this year. Do I fast on Friday or Sunday instead?"
"I usually fast on my father’s yahrzeit, but someone is honoring me with sandaka’us on that day. Do I fast, and do I need to be matir neder in the event that it is permitted to eat?"
The holiday approached and Rosh Hashanah arrived. Rabbi Amnon of Mainz asked his relatives to bring him to the synagogue with all of his dismembered organs and to place him by the prayer leader. We can well image the atmosphere in the synagogue.
In the past few years, nations have come upon us and demanded that we relinquish portions of the Land of Israel to strangers. This is one of the calamities concerning which we are supposed to fast and cry out to God about.
Two Views, Avnei Nezer's Proof, How a Renter Today is an "Owner”, Another Angle, The Ohr Samayach-Shach "Right of Usage”, A House with No Door, Summary