(Arabic: “God”), the one and only God in the religion of Islām. Etymologically, the name Allāh is probably a contraction of the Arabic al-Ilāh, “the God.” The name's origin can be traced back to the earliest Semitic writings in which the word for god was Il or El, the latter being an Old Testament synonym for Yahweh. Allāh is the standard Arabic word for “God” and is used by Arab Christians as well as by Muslims.

Allāh is the pivot of the Muslim faith. The Muslim holy scripture, the Qurʾān, constantly preaches Allāh's reality, his inaccessible mystery, his various names, and his actions on behalf of his creatures. Three themes preponderate: (1) Allāh is creator, judge, and rewarder; (2) he is unique (wāḥid) and inherently one (aḥad); and (3) he is omnipotent and all-merciful. God is the “Lord of the Worlds,” the most high, “nothing is like unto him,” and this in itself is to the believer a request to adore Allāh as protector and to glorify his powers of compassion and forgiveness.

God, says the Qurʾān, “loves those who do good,” and two passages in the Qurʾān express a mutual love between God and man, but the Judeo-Christian precept to “love God with all thy heart” is nowhere formulated in Islām. The emphasis is rather on God's inscrutable sovereignty, to which one must abandon oneself. In essence, the “surrender to Allāh” (islām) is the religion itself.

Muslim piety has collected, in the Qurʾān and in the Ḥadīth (the sayings of the Prophet Muḥammad (Muhammad)), the 99 “most beautiful names” (al-asmāʾ al-ḥusnā) of God, and these names have become objects of devoted recitation and meditation. Among the names of Allāh are the One and Only, the Living One, the Subsisting (al-Ḥayy al-Qayyūm), the Real Truth (al-Ḥaqq), the Sublime (al-ʿAẓīm), the Wise (al-Ḥakīm), the Omnipotent (al-ʿAzīz), the Hearer (as-Samīʿ), the Seer (al-Baṣīr), the Omniscient (al-ʿAlīm), the Witness (Shāhid), the Protector (al-Wakīl), the Benefactor (ar-Raḥmān), the Merciful (ar-Raḥīm), and the Constant Forgiver (Ghafūr, Ghaffār).

At all times there have been freethinkers in Islām, but rare indeed has been the Muslim thinker who has denied the very existence of God. Indeed, the profession of faith ( shahādah) by which a person is introduced into the Muslim community consists of the affirmation that there is no god but Allāh and that Muḥammad is his prophet. For pious Muslims, every action is opened by an invocation of the divine name ( basmalah). The formula inshāʾa Allāh, “if God wills,” appears frequently in daily speech. This formula is the reminder of an ever-present divine intervention in the order of the world and the actions of human beings. Muslims believe that nothing happens and nothing is performed unless it is by the will or commandment of Allāh. The personal attitude of a Muslim believer, therefore, is a complete submission to God, “whom one does not question” but whom one knows according to his (Qurʾānic) word to be a fair judge, at once formidable and benevolent, and the supreme help.