Birkat Hamazon: Knives on the Table
Question
Is it true that there can be no knives on the table when Birkat Hamazon is recited?
Answer
Shalom!
Thank you for your question.
Yes. Many people have the custom to cover or remove any knives from the table before the Birkat Hamazon is recited. The reason for this is that knives are compared to swords and our table is compared to the altar in the Temple. Swords shorten life while the altar (and mitzvot) lengthen life. Due to this clash, there is the custom to remove the knives.
There is another reason cited to either cover or remove the knives. There was once a person who became so distressed while reciting Birkat Hamazon as he mentioned and pondered the destruction of Jerusalem that he took a knife that was on the table and stabbed himself with it.
Finally, removing or covering knives also said to symbolize that the Angel of Death has no power over those who recite Birkat Hamazon carefully and with concentration.
The custom is not observed on Shabbat and holidays, as the holiness of these days serves to protect us from any possible trouble. The custom does not apply to plastic.
Source
OC 180:5; Rokei’ach 332; Sefer Chassidim 102; Shibolei Haleket 155; Kitzur Shulchan Aruch 44:4; Kaf Hachaim , OC 180:15; Mishna Berura 180:11; Elya Rabba 180:6; Aruch Hashulchan , OC 180:6; Da’at Kedoshim , Hilchot Stam 289:1; M ishna Berura 11:61;