It is known internationally that flying a flag at half-staff is a symbol of respect, mourning or distress. The half-staff days in the United States can be on scheduled dates or during impromptu national events. There are also half-staff days in foreign countries. However, there are some national flags that are never flown at half-staff.
Flags that are never flown at half-staff include: Saudi Arabia, Somalia, Iran, and Iraq. This is not done to be different or to stand out – each of the four flags represent the Shahada, which is an Islamic creed that declares belief in the oneness of god. The Shahada can be more easily explained as a declaration of the Islamic faith.
The most notable Shahada representation on the four flags is displayed on the Saudi Arabia flag. The Saudi Arabia flag features an Arabic inscription that reads “There is no god but God, Muhammed is the messenger of God”. Since the Shahada is considered holy, it will never appear on anything besides the flag itself. Flags representing the Shahada are never flown at half-staff because it is believed to be insulting to their God and their religion. It’s interesting to note that other Muslim countries will lower their flag to half-staff as a salute to these countries, but these four countries will never lower their own flag to half-staff.
American’s are more familiar with Shahada than they would think. The Taliban, one of America’s enemies during the War on Terror, flew a white flag with Shahada script written on it.
This is not really accurate, I know for a fact that Iranian flag has flown half-mast at death of known politician, Akbar Hashemi Rafsanjani.