All praise be to Allah, and peace and blessings be upon the Messenger of Allah, his family, his Companions, and those who follow his guidance.
There is, in the present time, a tradition in many Islamic countries that when a king or a leader dies, people must mourn for three days or more or less. Flags are lowered at half-mast and the State departments stop working.
Undoubtedly, these acts go against Shari`ah (Islamic law) and entail imitation of the enemies of Islam.
Authentic Hadiths related from the Prophet (peace be upon him) prohibit and warn people, except a wife, against mourning. The maximum period of mourning for a woman is four months and ten days, if the deceased is her husband, and three days or less for relatives. The other practices done during mourning a deceased person, whether a king or a leader, are prohibited in Shari`ah.
During the lifetime of the Prophet (peace be upon him), his son Ibrahim, his three daughters and others died, but he (peace be upon him) did not mourn them.
The leaders who joined the Battle of Mu’tah, including Zayd ibn Harithah, Ja`far ibn Abu Talib and `Abdullah ibn Rawahah (may Allah be pleased with them) were killed during the Prophet’s era but he (peace be upon him) did not mourn them.
Furthermore, the Sahabah (Companions of the Prophet) did not mourn the death of the Prophet (peace be upon him), the best of creation and prophets, nor did they mourn Abu Bakr Al-Siddiq (may Allah be pleased with him), the best of Sahabah and creation after the prophets. When `Umar, `Uthman and `Aly (may Allah be pleased with them), the best creation after the prophets and Abu Bakr Al-Siddiq, were killed, no one mourned them. The same was true with all the Sahabah and the Imams of Islam and guidance of Tabi`un (Followers, the generation after the Companions of the Prophet) and the next generation including Sa`id ibn Al-Musayyib, `Aly ibn Al-Husayn Zayn Al-`Abidin, his son Muhammad ibn `Aly, `Umar ibn `Abdul-`Aziz,Al-Zuhry, Imam Abu Hanifah, his two companions, Imam Malik ibn Anas, Al-Awza`y, Al-Thawry, Imam Al-Shafi`y, Imam Ahmad ibn Hanbal, and Is-haq ibn Rahawayh and many others. No Muslim mourned those people.
If this (mourning) were good, the Salaf (righteous predecessors) would have done it. All goodness lies in following them and evil lies in opposing them. Therefore, the Sunnah (whatever is reported from the Prophet) affirmed that what the Salaf did concerning avoiding mourning any person except for a dead husband, is the right action.
The mourning practiced nowadays for the death of kings and leaders is unacceptable in Islam. These practices entail imitating the enemies of Islam and result in much harm, such as suspension of public services. Consequently, the Muslim authorities and rulers must abandon these acts of mourning and follow the conduct of the Salaf.
Furthermore, the people of knowledge have to warn and inform Muslims about the ruling on these acts as they are obliged to advise people and cooperate in righteousness and piety.
I, therefore, for the sake of Allah, the Prophet (peace be upon him) and all Muslims, Imams and ordinary people, find it necessary to write this brief statement. I ask Allah (Glorified and Exalted be He) to grant Muslim rulers and subjects success to do what pleases Him and to follow Shari`ah and warn against opposing it. May Allah purify our hearts and deeds for He is the All-Hearer of supplication, the Ever-Near. May Allah’s Peace and blessings be upon our Prophet Muhammad, his family and Companions.
Source: Fatwas of Ibn Baz (rahimahullaah) – http://www.alifta.net
Sahih Bukhari : “Book of Menses”: No. 311 – Narrated Um-‘Atiya:
We were forbidden to mourn for a dead person for more than three days except in the case of a husband for whom mourning was allowed for four months and ten days. (During that time) we were not allowed to put kohl (antimony eye powder) in our eyes or to use perfumes or to put on colored clothes except a dress made of ‘Asb (a kind of Yemen cloth, very coarse and rough). We were allowed very light perfumes at the time of taking a bath after menses and also we were forbidden to go with the funeral procession.