U should not tear your pockets nor scotch your cheeks


Abd al-Razzaq al-Muqarram in his “Maqtal al-Hussein”, in chapter 49, “The Night Preceeding ‘Ashura” said:

‘Ali Ibn al-Husain (‘a) has said, “I heard my father on the night preceding the day on which he was killed saying, as he was mending his sword,
O Time! Fie upon you for a friend!
How many do you have, at dawn and at dusk
Of friends and of vengeance seekers,
While Time with a substitute is never pleased?
But the affair is with the Mighty One
And every living being will go his way.
“He repeated them twice or thrice; therefore, I understood his implication, so I was overcome with tears, yet I remained silent, knowing that fate was near. As for my aunt, Zainab (‘a), once she heard those verses, she leaped and went to see him.
She said to him, ‘Woe unto me! Shall I survive you?! I wish death had deprived me of life! My mother, Fatima (‘a), has just died followed by my father ‘Ali (‘a) then my brother al-Hasan (‘a)![543] O vicar of the past generations and the best remnant of those that remain!’ Al-Husain (‘a) consoled her and admonished her to persevere, telling her, ‘O sister! May Allah console you! Be informed that earthlings die, and that even those who live in the heavens do not live forever. Everything shall perish except His countenance; my consolation, and that of every Muslim, is that the Messenger of Allah (S) is our best example.’ She, peace be upon her, said to him, ‘Do you force yourself on it? This causes my heart to swell even more, and it surely is harder on my soul.'[544]
The women wept when they saw her weeping, beating their cheeks. Umm Kulthum cried out, ‘O Muhammad! O ‘Ali ! O mother! O Husain! How lost we are after you!’ Al-Husain (‘a) said, ‘O sister! O Umm Kulthum! O Fatima! O Rubab! Pay attention to me. Once I am killed, you should not tear your pockets nor scotch your cheeks nor utter any verbal abuse.'[545]

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[543] al-Tabari, Tarikh, Vol. 4, p. 240. Ibn al-Athir, Al-Kamil, Vol. 4, p. 24. Al-Khawarizmi, Maqtal al-Husain, Vol. 1, p. 238, Chapter 11. Abul-Faraj al-Ishfahani, Maqatil al-Talibiyyin, p. 45, Iranian edition.
[544] Ibn Nama, Al-Luhuf.
[545] al-Mufid, Al-Irshad.

Famous Abbas Qummi in his “Nafasul Mahmum”, chapter 21, “Relating to the events of the night of Āshoorā (the tenth of Muharram)” said:

Imām Ali Zainul Ābedeen (a.s.) says that on the night preceding the martyrdom of my father, I was awake while my aunt Hazrat Zaynab (a.s.) was attending to me. My father was alone in his tent, while Jaun, the re­tainer of Abu Zarr Ghifāri, was with him and was preparing his sword and putting it right. My father was reciting the following couplets:
“Time, shame on you as a friend, at the day’s dawning and the sun’s setting, how many a companion or seeker will be a corpse, time will not be satisfied with any substitute, the matter will rest with the Mighty One, and every living creature will have to journey along my path.”
He repeated it twice or thrice and I understood what he meant and sorrow befell me but I bore it silently and realized that a calamity had befallen us. My aunt Zaynab (a.s.) heard it too, sensitiveness and anxiety being the qualities of women, she could not control herself and tearing her clothes ran bareheaded towards my father and said, “Woe unto this tragedy! I wish death overtakes me. Today my mother Fatima (a.s.), my father Ali (a.s.) and my brother Hasan (a.s.) have departed from me. O successor of the departed ones! O source of hope for the alive ones!”
Imām turned towards his sister and said,
“O dear sister! Do not let Shaitān take away your forbearance.”
His eyes became full of tears and then he said,
“If a sand grouse (a type of a bird) is freed at night, it will sleep in peace.”
Then she said, “Woe! Then will you be violently and helplessly killed? While this hurts my heart and is severe upon my life.” Then she started beating her face and tore off her collar and fell unconscious. Then Imām arose and sprinkled water [refer Note No. 52] over her face and said,
“O dear sister! Control yourself and desire consolation from Allāh alone. And know that everyone upon the earth shall die, while the dwellers of the heavens too shall perish, except the Face (Self) of Allāh. Allāh who has created with His power, and will make them alive again, and they shall all return to Him, while Allāh is Unique. My grandfather was better than me, my father was better than me, and my mother was better than me. It is obligatory upon me and all Muslims to follow the example of the Prophet of Allāh (S).”
Then he consoled her with similar words and said,
“O dear sister! I request you on oath that when I am martyred, do not tear off your collar, nor beat your face or lament upon me.”

And here you can see how shias “following” to advice of their imam

http://fnoor.com/fn0051.htm