28) (Vayikra 10:6): "And Moses said to Aaron and to Elazar and to Ithamar, his sons: Your hair do not grow long … (Vayikra 10:7) and from the door of the tent of meeting do not go out.": From here they ruled: Those who were executed by beth-din are not to be attended upon for any purpose. "and from the door of the tent of meeting do not go out": From here they ruled: If a high-priest lost one of his kin, he does not follow the litter. When they (the members of the funeral cortege) are concealed (from his sight), he may reveal himself. When they are revealed, he must conceal himself. Lest you say: We shall go to our houses and mourn and grieve and wail, has the L–rd not commanded us not to leave the sanctuary? (Vayikra 10:6): "And let your brethren, the entire house of Israel, mourn the burning that the L–rd has burned … (Vayikra 10:7): and they did according to the word of Moses": They vindicated G d's judgment upon them and they were silent.
Aaron Forbidden to Mourn and the Silence That Vindicated the Judgment
Sifra, Mekhilta deMiluim II 28
[כח] "ויאמר משה אל אהרן ולאלעזר ולאיתמר". מכאן אמרו הרוגי בית דין אין מתעסקין עליהם לכל דבר. שמא תאמרו "אנו הולכים לבתינו ומתאבלים ואוננים ובוכים" – הלא פקד המקום שלא תצאו מבית הקדש שנאמר "ומפתח אהל מועד לא תצאו". מכאן אמרו כהן גדול שמת לו מת אינו יוצא אחר המטה. הם נכסים והוא נגלה, הם נגלים והוא נכסה. "ויעשו כדבר משה" – צדקו עליהם את הדין ושתקו.