The subject matter of Gan David is the halachic prohibition of doing any form of melachah (plural melachot) on Shabbat, with some exceptions. Though melachah is usually translated as "work" in English, the term does not correspond to the English definition of the term. The Talmud Tractate Shabbat (Ch7, Mishna 2), citing verses from the Torah, identifies 39 categories of activity prohibited on Shabbat (or 39 melachot, or lamed tet avot melachot), and clarifies many questions surrounding the application of the prohibitions. These activities are, with some exceptions, also prohibited on the Jewish holidays listed in the Torah. Many rabbinical scholars have pointed out that these regulations of labor have something in common - they prohibit any activity that is creative, or that exercises control or dominion over one's environment. The commandment to keep the Sabbath as a day of rest is repeated many times in the Tanakh, the Hebrew Bible. Its importance is also stressed in Exodus 31:12-17 which states ““G-d told Moses to speak to the Israelites and say to them: You must still keep my sabbaths. It is a sign between me and you for all generations, to make you realize that I, G-d, am making you holy. Keep the Sabbath as something sacred to you. Anyone doing work (melakhah - מְלָאכָה) shall be cut off spiritually from his people, and therefore, anyone violating it shall be put to death. Do your work (melakhah) during the six week days, but keep Saturday as a Sabbath of sabbaths, holy to G-d. Whoever does any work (melakhah) on Saturday shall be put to death. The Israelites shall thus keep the Sabbath, making it a day of rest for all generations, as an eternal covenant. It is a sign between me and the Israelites that during the six weekdays G-d made heaven and earth, but on Saturday, he ceased working and rested.”
דף [4,ב-9,א]: הקדמת בן המחבר. ובתוכה שו"ת שהוחלפו בין המחבר ובין ר' חיים אלעזר שפירא ממונקאטש "לענין מת ... בזמן שהי' ספק בין השמשות ... מתי תהי' היאצ"ט". שאלת המחבר הועתקה "משו"ת 'ויברך דוד' הנקרא שו"ת רדב"ם, כת"י", ותשובת רח"א
שפירא הועתקה "משו"ת 'מנחת אלעזר', חלק ה, סי' כג [צ"ל: ג], כת"י" [נדפס בשנת תשל"ד בברוקלין].