I
The "entire House" (both men and women) of Yisrael wept when Aharon died (Bamidbar 20:29), while when Moshe died only the "sons (lit. - children)" of Yisrael wept (Devarim 34:8). Rashi explains that Aharon pursued peace and instilled love between disputants, including a man and his wife, and therefore was mourned by all. Moshe was mourned primarily by the men to whom he taught Torah.
As the one who received the Torah from Hashem, Moshe's influence on all of Am Yisrael was unparalleled. And yet, his very closeness to Hashem limited his direct contact with the masses, and even his own wife (Rashi Bamidbar 12:8). Aharon, by contrast, had direct contact with the men and women as a peacemaker as well as teacher who turned many away from sin (Malachi 2: 6-7). As a result, the entire House of Israel wept when he died.
II
"Yehoshua is worthy of being rewarded for his service, for he would not depart from within [Moshe's] tent [of study]" (Rashi Bamidbar 27:16, see Shemos 33:11). Moshe saw the humility of Yehoshua (Targum Yonasan Bamidbar 13:16), a loyal student who remained as close as possible to his teacher. As such, Moshe transmitted the Torah to Yehoshua, his primary disciple (Avos 1:1). Rashi adds that Yehoshua "killed himself" in the tents of Torah (see Bamidbar 9:14, Brachos 63b) and earned a good name in the world.
Ibn Eza (Shemos ibid) notes that although Yeshoshua was 56 years old, he was called a "na'ar" to reflect the fact that he served ("u'm'sharso") Moshe selflessly and loyally, just as a young disciple would. Indeed, Yehoshua strove to merely reflect the radiance of Moshe as the moon reflects the light of the sun (Bava Basra 75a). It is precisely this humility and subservience that enabled Yehoshua to become Moshe's primary disciple and successor.
III
The late Rav Yehoshua ben R' Aharon Neuwirth zt"l, who passed away this week, combined the above attributes of Moshe's primary disciple, Yehoshua, and his brother, Aharon. Like Yehoshua, he toiled in the tents of Torah and earned a good name for his many acts on behalf of the Torah community. His closeness, loyalty, and subservience to his rebbe, Rav Shlomo Zalman Auerbach, enabled his now classic Shemiras Shabbos Kehilchasa, a masterpiece of clarity and exposition that spawned a new genre of Torah literature. Like Aharon, he tried to reach the entire house of Israel. In fact, the subtitle of his magnum opus is "Practical Halacha for the Jewish Home", and its text is accessible to, and studied by, men and women alike, and was translated, with his encouragement and supervision, into English.
First published in 1964, Shemiras Shabbos Kehilchasa was reissued in 1979 with many more, and copious, footnotes. Here, the author fulfilled "V'Yehoshua l'zekainim", exhibiting more profound Torah scholarship of his own and, more significantly, of his illustrious rebbe. The final version, printed in 2010, incorporates the comments of Rav Auerbach zt"l, and an introduction to Hilchos Shabbos which he had published as Vol III. In 1988, Vol II, on the positive mitzvos of Shabbos was released.
Unlike Aharon, when Yehoshua died, he was not eulogized properly, and Am Yisrael was nearly punished as a result (Shabbos 105b). The loss of Rav Yehoshua ben R' Aharon Neuwirth, zt"l, an unassuming giant of Torah, chessed and community leadership, must be eulogized by the entire House of Israel. May his Torah live on forever, and may his memory be a blessing for his family and Klal Yisrael.