הלכה על עירובין 4:13

Rav Nachman bar Yitzchak, however, resolves the apparent contradiction between Mishnayot differently. He claims that the Mishnah in Rosh Hashanah addresses victorious battles, when Jewish soldiers have no need to return beyond 2000 cubits. The Mishnah in Eruvin, according to Rav Nachman bar Yitzchak, is speaking of a time where the Jews regrettably lose a battle and thus fear remaining outside their homes. In such situations, they may return home even beyond the 2000 amot with their arms.¹¹Although the Gemara specifically mentions a case where Jews lost a battle, the Rambam (Hilchot Shabbat 27:17) appears to extrapolate from it that Jews may return all the way home in any situation where non-Jewish enemies pose a threat to Jews who remain within the techum of the emergency. The Rosh (Eruvin 4:5) cites the Maharam of Rothenburg as accepting the opinions of both Rav and Rav Nachman bar Yitzchak. A Jewish soldier may thus return all the way home only if he is scared that the enemy might attack him should he stay within 2000 amot of the battlefield. When the Jews are stronger and this concern does not exist, he may go only 2000 amot from the battle site, in accordance with Rav Nachman bar Yitzchak’s opinion. When the Jew is returning, he may carry his weapons in accordance with the view of Rav.¹²It is not entirely clear if he is permitted to carry his weapons during a time that the Jews are stronger and he is going only 2000 amot (see Teshuvot Minchat Shlomo, 1:8, p. 57), but a soldier may certainly carry his weapons in times of danger when he is traveling all the way home (see Shulchan Aruch, Orach Chaim 407:3).