Muslims engage in a variety of devotional practices to increase their God-consciousness (taqwā) and to discipline their attitudes toward others. Sunni Muslims have identified what they call the “five pillars of Islam” as a focus for their ritual practices, with some variation in how they are prescribed across Islamic legal schools. They are based on the Quran and Sunnah and were given their defining interpretations by the ‘ulamā’ in the first three centuries of Islam. The five pillars are: the shahādah [the testimony of the unity of God and the prophethood of Muhammad]; ṣalāt [canonical prayer]; zakāt [alms]; ṣawm [the fast of Ramadan]; and ḥajj [pilgrimage to Mecca. Although categorized in different ways, most Shi‘a accept these very same pillars, and many add that the acceptance of the authority and sanctity [wilāyah] of the Imams is also a pillar.
Although the canonical prayers, alms, pilgrimage and fast of Ramadan are almost universally shared among Muslims, there is nonetheless much room for diversity in Islamic practice. The canonical prayers can be performed individually or in congregation at the mosque or literally anywhere else. The Friday prayers are a weekly gathering in which Muslims listen to a sermon and pray together. At homes and in the mosque, the sight of Muslims reciting the Quran or using prayer beads for the invocation of sacred litanies or particular praises of God or the Prophet is common. However, mosques are not the only places that Muslims gather to worship, as diverse communities have meeting places suited to their particular needs, including Sufi lodges (zāwiyah, tekke or khānaqāh) and shrines [maqām, dargāh, mazār], Ismaili houses of congregation [jamā‘at-khanah] and Twelver Shi‘ite husayniyyahs and imāmbaras, which supplement or sometimes replace the activities of the mosque.
Worship is of course not limited to any particular space or time, and personal supplications [du‘ā] are typically made throughout the day regarding both worldly and spiritual topics, and there is a wide range of formalized supplications passed down from the Prophet, the Imams, or other holy figures. Many practice the invocation of a sacred formula, often a Name of God, verse of the Quran or the testification “there is no god but God.” This invocatory practice, called dhikr, is the central mystical rite of Sufis, who under the guidance of the Sufi master [shaykh] use this practice to cultivate constant remembrance of God. In some Sufi orders, communal practices of invocation are accompanied by music and ritual forms of dance, known as samā‘ or haḍrah. Although dhikr is most popularly associated with Sufism, it is a common form of worship in many Muslim communities.
Throughout the year, a number of festivities are held, such as the ‘Eid al-Aḍḥa, which celebrates the Prophet Abraham's willingness to sacrifice his lineage in service of God and is the culmination of the ḥajj. In Shi‘i communities, certain days throughout the year are dedicated to particular events in the lives of the Imams and commemorated through practices such as fasting, charitable acts, and prayer; the most important of these as mentioned above is ‘Āshūrah, which commemorates the martyrdom of the Prophet’s grandson, Husayn, in 680 CE. The attention to sacred times in the Islamic calendar is complemented by the importance of sacred space. Many visit the shrines of prophets and holy figures, as well as sites at which some event in their tradition’s sacred history had transpired, seeking a prayer answered or the contemplative ambience of the sacred. This practice is commonly known as ziyārah. For most Muslims, the most important mazār (place of visitation) is the Prophet’s own mosque and tomb in the city of Medina.
Islamic creed has been formulated in many different ways within the Islamic tradition; on many issues there are diverse points of view, yet there is also consistency on many fundamental beliefs. The shared foundations of the Islamic creed include belief in the oneness of God, affirmation of the prophethood of Muhammad as the last messenger sent to mankind, and the expectation of the final return to God. On the basis of Quranic teachings, Islamic belief also recognizes that we inhabit a living spiritual cosmos, containing angels and jinn, which interact with humans and have the capacity to worship God. The Quran sees its message as the affirmation of the many revelations that have preceded it; for each civilization there has been a revealed religion that includes both a revelation and a messenger. These central points of Islamic creed are summarized in the Quranic verse: "The Messenger has believed in what was revealed to him from his Lord, and so have the believers. All of them have believed in Allah, His angels, His books and His messengers, [saying], ‘We make no distinction between any of His messengers.’ And they say, ‘We hear and we obey. [We seek] Your forgiveness, our Lord, and to You is the final destination’” (2:285).
The Islamic tradition has fostered a wide variety of approaches to understanding and conclusions about the nature of God, the world we live in, and the nature of humanity. Various disciplines have emerged that deal with these questions, including a wide variety of theological, philosophical and mystical schools. Over the centuries there has been much discussion of revelation, reason and mystical insights as sources of knowledge, leading to rich traditions of inquiry in both prose and poetry questions such as freewill, the relation of God and creation, and the possibility of a finite being knowing the Infinite. Muslim intellectuals have also engaged in the natural sciences, seeing no conflict between belief in God and study of the natural world, which the Quran declares to be filled with the signs of God. Although the technical discussions of theology, philosophy, and mysticism in Muslim cultures required a great deal of specialized training, all strata of society participated in questions of the nature of reality, humanity and the cultivation of character through the composition, recitation and performance of diverse literary forms, in Arabic, Persian and the many vernacular languages of Muslim communities.