Ramadan, one of the pillars of Islam, begins this week

For nearly a quarter of the world population, Monday marks the start of Ramadan, a month-long holiday of fasting, prayer, spirituality, and charity.

Most of the world's 1.6 billion Muslims will start the holiday Monday evening, including in the countries of Saudi Arabia and Indonesia, home to world's most Muslims. Because Islam follows a lunar calendar, a country's moon-sighting council often announces the start of the holiday. Iran and Pakistan had not yet proclaimed the start date of Ramadan, so it could begin there a day or two afterward.

As relations between Muslims and Westerners remain fraught with tension because of extremism and the migrant crisis, Ramadan serves as a reminder of the peaceful qualities of the world's fastest growing religion.

Ramadan, the ninth month on the Muslim calendar, is celebrated as the month when the first verses of the Quran were said to be revealed to the prophet Muhammad in 610 AD. Muslims traditionally commemorate the month by focusing and prayer, spirituality, and charity "to purify the body and mind." From sunrise to sunset, they abstain from food, drink, or other pleasures such as cigarettes and coffee. Certain groups such as children, the elderly, and pregnant women are excluded. Although much of the Islamic world spends the month coming together and reflecting, it isn't the case for all Muslims, as the Christian Science Monitor's Howard LaFranchi reported in June of last year:

Radical Islamists and the Islamic State in particular have focused on Ramadan as a period of intensified jihad, or holy war, when Sunni Muslims should lash out at both nonbelievers and Shiite Muslims.

'It's counterintuitive, you'd think [Ramadan] would be a time of turning inward, but for some [extremists] it's also a time when your holy obligation to fight against the nonbelievers and blasphemers becomes even more imperative,' says Marvin Weinbaum, a former south Asia intelligence analyst at the State Department who is now a resident scholar at the Middle East Institute in Washington. 

'Clearly these acts are planned,' he adds, 'and it wouldn't seem to be simply by coincidence that they occur during a period that increases the fervor that some feel about their religious obligations.' "

Indeed, extremist attacks are against the spirit of the holiday, which even instructs Muslims to abstain from gossip and other impurities to grow closer to God and their neighbors. Many spend the daytime reading the Quran and listening to religious lectures, and the evening in prayer in a mosque for a period known as "taraweeh." Following this prayer service, families and friends often come together to break the fast, and charities provide free meals at mosques and other public spaces. Some even break the fast as the prophet Muhammad did 1,400 years ago, with a sip of water and dates.

Ramadan is one of the five pillars of Islam, a religion that is on pace to become the world's most practiced religion by the end of the century, according to the Pew Research Center. Yet, it's a religion that's not often understood by Westerners, especially in the United States, where view Muslims "rather cooly," according to Pew. Although favorability of Muslims in Europe is better, last year's attacks in Paris and Brussels, coupled with the inundating stream of Muslim refugees overwhelming many European nations, have further strained relations between many Europeans and Muslims. 

This report contains material from the Associated Press.