17 Jun WHEN TO ATTACK IRAN

I. A Time for War
Early morning last
Friday, Israel attacked
Iran in a multi-pronged
effort that was wildly
successful in its initial
stages and we pray will
continue to succeed.
Koheles (3:6) notwithstanding, there is never
a good time for war. We hope and pray for
a time when there will be no war. But when
war is necessary, presumably there should
be no time constraints to it. However, the
halachah is otherwise, as we will see. If the
Israeli Defense Forces were run completely
according to halachah, which they currently
are not, would a Friday morning have been a
halachically appropriate time to attack?
The Gemara (Shabbos 19a) quotes a baraisa
which says: “One may not lay siege to the
gentiles’ cities fewer than three days before
Shabbos. If they already began, they need
not stop. And so Shammai would say: ‘[And
you should build a siege against the city that
is waging war with you] until it falls’ (Deut.
20:20), even on Shabbos.” According to this
view, we may not begin a battle within three
days before Shabbos. Rashi (Deut. 20:19)
quotes the Sifrei which says that this rule is
derived from the preceding verse, “If you
besiege a city many days to wage war against

it to capture it….” The plural word “days”
(yamim) implies two days. The additional
word “many” (rabim) implies more than
two days, namely three days. Rav David
Segal (known as the Taz) explains that you
wage war “until it falls,” even on Shabbos,
only if the war started at least three days
earlier (Divrei David, ad loc.). However,
most commentators agree with Rav Eliyahu
Mizrachi (commentary, ad loc.) that this is a
rabbinical rule.
II. Three Days Before Shabbos
Commentators offer different reasons for this
rule of starting a battle only three or more
days before Shabbos. Rav Yitzchak Alfasi
(Rif, Shabbos 7b) explains that it takes three
days to calm down from an attack and enjoy
Shabbos. Rav Zerachiah Ha-Levi (Ha-Ma’or
Ha-Katan, ad loc., 7a) explains that if within
three days before Shabbos you put yourself
in a position in which you will have to violate
Shabbos, it is as if you are intentionally
violating Shabbos. Later commentators
accept one or the other explanations.
However, the first approach requires more
elaboration. It assumes that a battle will take
only one day and then the soldiers rest and
calm down until Shabbos. Is that always, or
even usually, the case? We will return to this
question below.

Rambam seems to contradict

himself about this three-day-
before-Shabbos rule. In two

places in Mishneh Torah (Hilchos
Shabbos 2:25, 30:13), Rambam
writes that we may not lay siege
to a city within three days before
Shabbos. He explicitly adopts
Rav Alfasi’s explanation, that this
rule is to allow soldiers to call
down in time for Shabbos (30:13).
Rambam distinguishes between
laying a siege and fighting a
battle. You may not lay a siege
within three days before Shabbos
but you may fight a battle any day
of the week. However, elsewhere Rambam
omits the three-days-before-Shabbos rule:
”One may lay siege to the gentiles’ cities and
one may engage in battle with them every
day, even on Shabbos, as it says, ‘until it falls’
(Deut. 20:20), even on Shabbos. This applies
to both a mitzvah war and a permissible war.”
(Mishneh Torah, Hilchos Melachim 6:11)
III. Two Approaches
Why doesn’t Rambam mention the limitation
of three days before Shabbos in Hilchos
Melachim? There are two main approaches
to answering this question. Rav Yosef Karo
(16th cen., Israel) asserts that the text must
be mistaken and therefore he amends it
to: “One may lay siege to the gentiles’
cities three days before Shabbos” (Kessef
Mishneh, Hilchos Shabbos 2:25). Later
commentators explain that according to this
approach, the key distinction is whether
the army is laying a siege or engaging in
battle. A siege requires an initial effort to
surround a city and then a lengthy period
of waiting and holding the siege. An army
should lay a siege at least three days before
Shabbos so that the siege will be complete
and soldiers will have time to calm down
by Shabbos. In contrast, a battle lasts a long
time. Therefore, it does not matter on which

day it begins. Only a siege has the three-
day-before-Shabbos rule.

Rav Moshe Lifschitz (16th cen., Russia)
takes a different approach (Lechem
Mishneh, Hilchos Melachim 6:11). He

argues that Rambam mentions the three-
day-before-Shabbos rule in Hilkos Shabbos

and therefore does not need to repeat it.
The key distinction for Rambam is between
a mitzvah war (milchemes mitzvah) and
a permissible war (milchemes reshus). A
permissible war, whether a siege or a battle,
must be started at least three days before
Shabbos. A mitzvah war may begin on any
day of the week, even Shabbos.
Rav Yitzchak Ben Sheishes Prefet (Rivash,
15th cen., Spain-Algeria) seems to follow
an approach similar to Rav Lifschitz’s
explanation of Rambam’s view. He applies
the three-day-before-Shabbos rule only to
a permissible war (Responsa Rivash, no.

101). Rav Ya’akov Ben Asher (14th cen.,
Spain) writes likewise (Tur, Orach Chaim
249). In contrast, Rav David Ibn Zimra
(Radbaz, 16th cen., Egypt) seems to take an
approach similar to Rav Karo’s explanation
of Rambam’s view. He does not distinguish
between a mitzvah war and a permissible war
(Responsa Radbaz, vol. 4, no. 77). However,
rather than amending Rambam’s text, Radbaz
suggests that Rambam is discussing holding
a siege, not laying it. You may hold the siege
any day of the week, even Shabbos. But you
only lay the siege at least three days before
Shabbos.
IV. Attacking Iran
Rav Shlomo Goren (20th cen., Israel) follows
Rav Yosef Karo’s approach, that a siege must
be laid at least three days before Shabbos
but a war may be started any day of the
week (Meishiv Milchamah, vol. 1, part 1,
no. 2). Rav Eliezer Waldenburg takes this
approach, as well (20th cen., Israel; Hilchos
Medinah, vol. 2, part 10, ch. 3, par. 11). Rav
Nachum Rabinovitch does also (Melumedei
Milchamah, no. 36). According to these
authorities, you may attack any day of the
week. Since the attack on Iran is a battle and
not a siege, the three-days-before-Shabbos
rule does not apply.
However, Rav Rabinovitch’s colleague, Rav
Yitzchak Shilat, adopts the approach of Rav
Lifschitz and not Rav Karo. Rav Shilat has
not only retranslated and published many
of Rambam’s writings, he also published
an edition of Mishneh Torah titled Rambam
Meduyak (Jerusalem, 2021), which is based
on the best Egyptian, Syrian and Israeli
manuscripts. In his recently published
Medinah, Halachah Ve-Kavanos Ha-Torah
(Jerusalem, 2023), Rav Shilat says that there
is no textual basis for Rav Yosef Karo’s
emendation (pp. 300-305). Instead, he
accepts the distinction between a mitzvah war
and a permissible war. Rav Yitzchak Herzog
(20th cen., Israel) rules likewise (Heichal
Yitzchak, Orach Chaim 37:3). The question
then becomes whether invading Iran is a
mitzvah war or a permissible war. Given that
Iran has threatened to annihilate Israel and is
attempting to build the capability to do so,
this would qualify as a defensive mitzvah war
which may be started any day of the week.