Shi'a Islam incorporates Tawhīd as one of the Roots of Religion. Sunni Islam incorporates Tawhīd as one of the seven aspects of Aqidah (Islamic Creed). Lā 'ilāha 'illā llāha (There is no god except Allah) is a common expression of Tawhīd by Sunni and Shia Muslims.

Verses from the Holy Qur'ān

Being the foundation of Islamic beliefs, Tawhid is explained throughout much of the Holy Qur'ān. Below are a few verses that refer to such belief:

"In the Name of Allah, the Most Beneficient, the Most Merciful,

Say: He is Allah, the One,

Allah is He on whom all depend,

He does not beget, nor is He begotten,

And (there is) none like Him." (The Holy Qur'ān, 112:1-4)

The above chapter, al-Ikhlās (the Sincerity; the Unity; to Purify), consists of four verses. It is commonly recited as part of the five daily prayers (salah).

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Aspects of Tawhid

Tawhid has three aspects: Tawhid ar-Rububiyya, Tawhid al-Asma wa as-Sifat and Tawhid al-ibāda. For Muslims, acceptance of only one aspect of Tawhid is not enough.

Tawhid ar-Rububiyya

Tawhid ar-Rububiyya (Oneness of God's Lordship) is the conviction that God, and only God, creates and sustains the universe, that without his will the universe could not continue to exist. Muslims believe that associating anything or anyone with God as Lord is a sin which God will never forgive, because failure to hold this conviction results in either polytheism or atheism. This aspect of Tawheed is expressed in the following verses from the Quran.

"God is the Creator of everything. He is the guardian over everything. Unto Him belong the keys of the heavens and the earth." (The Holy Qur'an, 39:62-63).

"No creature is there crawling on the earth, but its provision rests on God. He knows its lodging place and it repository." (The Holy Qur'an 11:6).

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Tawhid al-Asma wa al-Sifat

Tawhid al-Asma wa as-Sifat (Oneness of God's Names and of Attributes) is the conviction that God has certain names and characteristics which He mentioned in the Qur'an or in the sayings of the Prophet Muhammad (Sunnah). It is the belief that nothing resembles God, nor does He resemble any of His creation. The idea that God rested on the seventh day of creation, that God is an envious plotter against mankind, or that God is incarnate in any human being are considered blasphemy from the Islamic point of view.

This aspect of Tawheed includes the belief in the ninety-nine attributes describing God. Muslims believe that God has provided humankind with these descriptions so that they can know God. Islam teaches that only an analysis of these ninety-nine attributes will enable at least a basic understanding of the concept of the Oneness of God. Muslims believe these attributes to be eternal and everlasting. This aspect of Tawhid is expressed in the following verses from the Qur'an.

22) "He is God; there is no god but He, He is the Knower of the unseen and the visible; He is the All-Merciful, the All-Compassionate.

23) He is God, there is no God but He. He is the King, the All-Holy, the All-Peace, the Guardian of Faith, the All-Preserver, the All-Mighty, the All-Compeller, the All-Sublime. Glory be to God, above that which they associate!

24) He is God the Creator, the Maker, the Shaper. To Him belong the Names Most Beautiful. All that is in the heavens and the earth magnifies Him; He is the All-Mighty, the All-Wise." (The Holy Qur'an, 59:22-24).

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Tawhid al-Ibāda

Tawhid al-Ibada (Oneness of God's Worship) means "declaring God one through our service," to worship none other than God in all actions, words and thoughts; whether the actions, words and thought are visible to others or hidden. This includes the belief that no action, word or thought should be committed for any reason other than to seek God's approval. This requires one to worship God alone, with pure and sincere intent and dedication. Worship includes any action done in servitude to God which He commanded, such as prayer, supplication, sacrifice, vowing, love and fear. This aspect of Tawhid is expressed in the following verses from the Qur'an.

"Do you worship what you have carved yourself?" (The Holy Qur'an 37:95).

"Or have you taken unto you others beside Him to be your protectors, even such as have no power either for good or for harm to themselves?" (The Holy Qur'an, 13:16).

Thus, true monotheism in Islam requires one to have the correct knowledge (tawhid ar-rububiyya), the correct understanding (tawhid al-asma wa as-sifat), and the correct motivation (tawhid al-ibada).

In Nahj al-Balagha Ali has famously stated:

"Praise is due to Allah whose worth cannot be described by speakers, whose bounties cannot be counted by calculators and whose claim (to obedience) cannot be satisfied by those who attempt to do so, whom the height of intellectual courage cannot appreciate, and the divings of understanding cannot reach; He for whose description no limit has been laid down, no eulogy exists, no time is ordained and no duration is fixed. He brought forth creation through His Omnipotence, dispersed winds through His Compassion, and made firm the shaking earth with rocks.

The foremost in religion is the acknowledgement of Him, the perfection of acknowledging Him is to testify Him, the perfection of testifying Him is to believe in His Oneness, the perfection of believing in His Oneness is to regard Him Pure, and the perfection of His purity is to deny Him attributes, because every attribute is a proof that it is different from that to which it is attributed and everything to which something is attributed is different from the attribute. Thus whoever attaches attributes to Allah recognises His like, and who recognises His like regards Him two; and who regards Him two recognises parts for Him; and who recognises parts for Him mistook Him; and who mistook Him pointed at Him; and who pointed at Him admitted limitations for Him; and who admitted limitations for Him numbered Him.

Whoever said in what is He, held that He is contained; and whoever said on what is He held He is not on something else. He is a Being but not through phenomenon of coming into being. He exists but not from non-existence. He is with everything but not in physical nearness. He is different from everything but not in physical separation. He acts but without connotation of movements and instruments. He sees even when there is none to be looked at from among His creation. He is only One, such that there is none with whom He may keep company or whom He may miss in his absence.

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