I'd heard that some people have a custom not to give knives as a gift (as knives are a sign of shortening life, not extending it); I asked one rabbi who said he hadn't heard of such a custom, but it seemed reasonable. Does anyone have a source for this custom? Would it therefore be advisable not to register for kitchen knives as part of a bridal registry?
"[Rabbi Nachman of Breslev said] in the name of the Ba'al Shem Tov, one should not give his fellow a knife as a gift" (Sichot Haran no. 9, first printed in 1815. Maaglei Tzedek pg. 3a. This tradition is also found in Baal Shem Tov al Hatorah, Parshas Re’ah in the Mekor Mayim Chaim, no. 6.).
There is an in depth article about this issue by Bency Eichorn on the Sefarim blog. In there he says that the earliest Jewish source is the aforementioned Sichot Haran. The non-Jewish sources for this custom predate the Jewish source by over 300 years. He also brings other students of the Ba'al Shem Tov who would give knives as gifts.
Rav Bentzion Mutzafi says there is no source for the custom of not handing someone a knife, but then he says "maybe for being careful for a good (cause)."
שאלה - 2673 שלום לכבוד הרב הגאון האם יש מקור לדבר שאסור להעביר סכין מיד ליד אלה להניח על השולחן ולקחת או שזה סתם שטות והמצאה? תשובה אין לזה מקור, ואולי זה ענין של זהירות טובה
Translation: Hello to the honorable Rabbi-Scholar. My question is: is there a source that it is forbidden to pass a knife from a hand to another hand but rather to set it down onto the table and pick it up, or is this just nonsense and an invention (i.e., a new custom)? Response: There is no source to this, and maybe this is a concern for exercising appropriate caution.