Rambam In-Depth: Why Do We Make a Bracha on a Guardrail?

Welcome to Rambam In-Depth: Hilchos Rotzeach u’Shmiras HaNefesh, Perek Yud-Alef, Halacha Alef.

If the guardrail on your roof is there to prevent a fall, why does the Rambam have you make a bracha on building it — when he rules that mitzvos done purely to avoid danger, like mayim acharonim, get no bracha at all? And if it’s about danger, why is a barn, a warehouse, or a small house exempt?

The Rambam rules (Hilchos Rotzeach u’Shmiras HaNefesh 11:1): “Mitzvas asei la’asos adam ma’akeh l’gago” — it is a positive commandment to build a guardrail on one’s roof, as the Torah says, “v’asisa ma’akeh l’gagecha” (Devarim 22:8). Then come the qualifications: only a beis dirah, a dwelling; not a storehouse, not a barn; and any house smaller than four by four amos is exempt.

In this shiur, Rabbi Greenberg traces the answer through a question that was once put to the Rebbe. The Rebbe’s resolution: the mitzvas asei of ma’akeh is independent of the lav of “lo sasim damim b’veisecha.” The Torah is not giving one safety law with a reason attached — it is giving two mitzvos. The proof is the Rambam’s own klal in Sefer HaMitzvos: a reason given for a mitzvah is never counted as a mitzvah of its own. Since ma’akeh and lo sasim damim are both counted among the Taryag Mitzvos, the second cannot merely be the reason for the first.

The Pri Megadim reaches the same place from the other direction, and the Minchas Chinuch’s ruling — that a ma’akeh built by a goy, or by a cheresh, shoteh v’katan, does not fulfill the mitzvah — only makes sense once you see the mitzvah this way.

🔎 In this video we explore: • The Rambam’s exact words: who must build a ma’akeh, and the three cases that are exempt • The question: if a railing is about danger, what difference does four-by-four amos make? • Why the Rambam has you make a bracha on a ma’akeh but not on mayim acharonim • The Rebbe’s answer — the asei of ma’akeh is independent of the lav of lo sasim damim b’veisecha • The proof from Sefer HaMitzvos: a reason is never counted as a separate mitzvah • The Pri Megadim: “shomer pesa’im Hashem” — why falling off a roof is not a likely danger • When a definite danger (bari hezeika) obligates a guardrail even where the Torah exempts you • The Minchas Chinuch: why a ma’akeh built by a non-Jew doesn’t count — yourself or your shliach only

💡 Key Insights:

• Ma’akeh is not the Torah’s “building code” — it is a mitzvah in its own right, with its own bracha.
• Where the Torah exempts you (barn, storehouse, under four amos), there is no asei — but a real danger still obligates you under lo sasim damim.
• Who builds it matters: like any mitzvas asei, it must be done by you or your shliach.

📚 Sources discussed: Rambam, Hilchos Rotzeach u’Shmiras HaNefesh 11:1–2; Devarim 22:8 (v’asisa ma’akeh l’gagecha / lo sasim damim b’veisecha); Rambam, Hilchos Brachos (the bracha on ma’akeh; no bracha on mayim acharonim); Rambam, Sefer HaMitzvos (the klal that a mitzvah’s reason is not counted among the Taryag Mitzvos); the Lubavitcher Rebbe; Pri Megadim, Pesicha l’Hilchos Netilas Yadayim; Tehillim 116:6 (shomer pesa’im Hashem); Minchas Chinuch