He is not one of us who slaps the cheeks, splits the collars, and calls out with the calls of Jāhiliyyah (pre-Islamic era of ignorance)

The Prophet (may Allah's peace and blessings be upon him) forbade and warned against some of the practices of the people of Jāhliyyah, saying: He is not one of us: First: The one who slaps the cheeks, and the cheek is mentioned in particular because it is the part usually slapped; otherwise, slapping the rest of the face is included in the prohibition. Second: The one who splits the opened part of the garment through which the head is entered due to severe discontentment. Third: The one who calls out with the calls of the people of Jāhiliyyah, like supplicating for ruin and destruction, wailing, lamenting, etc.

1. The threat in the Hadīth denotes that such acts are from the major sins.
2. It is obligatory to adopt patience in dealing with calamities. It is prohibited to express discontent about the painful experiences predestined by Allah through wailing, lamenting, shaving, tearing clothes, etc.
3. It is prohibited to imitate the practices of Jāhiliyyah that have not been approved by the Legislator.
4. There is nothing wrong with sadness and crying, as they do not contradict patience with Allah's predestination; rather, they are a mercy that Allah has placed in the hearts of relatives and loved ones.
5. A Muslim should be content with Allah's predestination, and if he does not feel content, then patience is obligatory upon him.

صحيح البخاري (2/ 81) (1294). صحيح مسلم (1/ 99) (103). تيسير العلام شرح عمدة الأحكام، لعبد الله البسام (ص287). تنبيه الأفهام شرح عمدة الأحكام، لابن عثيمين (2/ 379) .