The initial basis for Islam's unity--which from AD 625 took only one century to spread across Persia to the east and the Mediterranean Levant, Africa, and Europe to the west--was the Islamic scripture, the holy Quran. It consists of revelations made by Allah to Muhammad and asks for guidance:
Guide us to the straight Way, the Way of those on whom you have bestowed Your Grace, not (the way) of those who earned Your Anger (such as the Jews), nor of those who went astray (such as the Christians) (Quran, Al-FGtihah 6-7).
The major preoccupation of doctrinaire Islam is living by God's will. The major ways of doing so involve "religious and social duties" (Ruthven, 2000, p. 79), which are contained in Islam's five pillars of wisdom:
Shahada. Reciting the basic declaration of faith.
Salat. Worship performed five times daily--dawn, noon, midafternoon, sunset, evening. Congregations gather in mosques on Fridays at noon.
Zakat. Compulsory charity for the poor. Historically, at the rate of "2.5 per cent of capital assets over and above a minimum known as the nisab." Today, according to conscience.
Sawm. Daily fasting during the month of Ramadan.
Hajj. Pilgrimage to Mecca during one's lifetime; the major hajj of Islam is performed annually (Ruthven, 2000, pp. 140-1, adapted).
The pillars of wisdom are connected to ritual. Salat requires all worshippers to face toward Mecca and to otherwise observe proper prayer form. Sawm affects daily behavior beyond prayers per se. Hajj goes beyond daily behavior to encompass a core purpose of life. However, the number of pilgrims allowed at the annual hajj is "limited by a quota system operated by the Saudi authorities" (Ruthven, 2000, p. 143).
Hajj involves specific rituals that have been historically difficult to observe not least because of Islam's origin: the Arabian desert. However, that has changed with modernity. Consider the Sa'I, or running seven times between hills of Safa a...