Foundations of Faith (Usul al-Din)
Proof of the Unity of God (al-Tawḥīd – التوحيد)
The belief in the existence and oneness of Allah (SWT) is embedded in the soul of every human being. It is the bedrock of all Islamic teachings and the most fundamental principle of the faith. What follows is a Qur’an-rooted, rational, and reflective explanation of this essential monotheistic belief.
1. The Name "Allah" Contains the Concept of Oneness
The word Allah in Arabic is composed of Al + Ilah, meaning The One and Only Deity Worthy of Worship. This name itself affirms unity (Tawḥīd)—that Allah (SWT) is the only one deserving of love, praise, worship, and obedience.
By contrast, the term “God” in English is generic, applied to beings imagined with gender, form, or plurality—gods, goddesses, demi-gods—all rooted in human imagination and ignorance. None of Allah’s appointed messengers—Moses, Jesus, or Muhammad (peace be upon them)—ever used such terms. They called on Allah, the Eternal, Unique, and Absolute.
2. There Cannot Be More Than One God
The Qur’an presents a logical, rhetorical challenge in verses 21:21–24:
If there were multiple gods, each would strive to dominate the other. Dispute, contradiction, and collapse would follow.
But the flawless harmony of the universe—its design, laws, and balance—proves that there is only One Supreme Being.
It is impossible for two beings to be equally omniscient, omnipotent, and all-present.
Ask yourself:
Can any being other than Allah (SWT) create a book like the Qur’an or raise divinely appointed Guides such as Adam, Abraham, Moses, Jesus, Muhammad, Ali, Fatima, Hasan, and Husain (peace be upon them)? If not, then the declaration in Surah al-Ikhlas (112) must be accepted:
Say: He is Allah, the One;
Allah, the Eternal, Absolute;
He begetteth not, nor is He begotten;
And there is none like unto Him.
3. Challenge to Polytheists
Allah (SWT) created all things in complementary pairs—from the natural world to the spiritual. For example, the spiritual pair of the Prophet Muhammad (SAW) and Imam ‘Ali (AS), per Qur’an 3:61, illustrates that everything in creation is interdependent. But all creation depends entirely on Allah (SWT), who is independent of all.
Can a polytheist survive without breathing the air created by Allah? Or using His sun, His water, His provision? How then can one deny His Oneness—or claim their deity is different?
4. Scientific Proof of Unity
Modern science, in its search for order, has only scratched the surface of Allah’s (SWT) intelligent design.
Genetics reveals Allah’s knowledge: the complexity of DNA shows planning beyond human grasp.
Natural phenomena like earthquakes or hurricanes show His power.
Landscapes and ecosystems reflect His beauty and harmony.
All of creation points to One Designer—not many.
5. Knowing Allah (SWT) Through His Chosen Guides
To worship Allah (SWT) meaningfully, we must understand His Attributes. These are beyond human comprehension—but He revealed them to us through His appointed Prophets and Imams, who were infallible, pure, and truthful.
Imam ‘Ali (AS), in Nahjul Balaghah, supplicates:
“Oh He whom no one knows what He is, or how He is, or where He is… and yet we know that He is.”
In Du‘a Kumayl, he prays:
“Oh God, I ask Thee by Thy mercy, which encompasses all things… by Thy strength, through which Thou dominatest all things… by Thy face, which subsists after all else is gone…”
Imam Ja‘far al-Ṣādiq (AS), teacher to the founders of Sunni schools of jurisprudence, corrected Imam Abu Hanifa’s understanding of the phrase “Allāhu Akbar.” He explained:
“It does not mean ‘Allah is the greatest,’ because that implies comparison.
It means ‘Allah is too great to be grasped or compared.’”
Legends (Glossary)
SWT — Subḥānahu wa Ta‘ālā: "Glory be to Him." Used after the name Allah.
SA — Ṣallallāhu ʿalayhi wa ālihi wa sallam: "Peace and blessings upon Muhammad and his family."
AS — ʿAlayhi (or her or him) al-salām: Peace upon him/her/them. Used for Prophets and their successors.
Q:xxx:yyy — Denotes chapter (sūrah) and verse (āyah) of the Qur’an.