All the basic principles of Islam are fully dealt with in the Holy Quran, and so is the doctrine of faith in God, where of the corner stone is belief in the unity of God. Tawhid is the most important Islamic belief. The Unity of God, according to the Holy Quran, implies that God is One in His person (dhat), One in His attributes (Sifat) and One in His works (af'al). His oneness in His person means there is neither plurality of gods, or plurality of persons in the Godhead; and who is wajib-ul-Wujud i.e. One whose existence is a must and non-existence impossible. Wajib-ul-Wujud is one who is eternal. He has no beginning and no end. Nothing in the world can be self-existent except the Almighty Allah. His Oneness in attributes implies that no other being possesses one or more of the Divine attributes in perfection; His Oneness in work implies that none can do the works which God has done, or which God may do. i.e. Everything on this earth is from the One and Only creator, who is also the Sustainer of the universe and the sole source of its Guidance.

Tawhid is the belief in Allah with all His powers. Allah is All-knowing, All-wise and All-powerful. The best-known expression of Divine Unity is that contained in 'la ilah ill-Allah'. It is made up of four words, la (no), ilah (that which is worshipped), illa (except) and Allah (the proper name of the Divine Being). Thus, these words, which are commonly rendered in English as meaning, 'there is no god but Allah', convey the significance that there is nothing which deserves to be worshipped except Allah. It is this confession which when combined with the confession of the prophethood of Muhammad - Muhammad-ur-Rasulullah, - admits a man into the fold of Islam. And this is the first duty of a Muslim to declare his faith that 'there is no god but Allah; Muhammad is Allah's messenger.' To make his declaration of faith a person must say in words and believe in his heart - 'la ilaha illal lahu Muhammadur rasulullah.'

Tawhid shapes and regulates the entire course of our life. This is why we must understand the meaning of Tawhid. It is the main part of Iman (faith) and is beautifully expressed in the Suratul-Ikhlas of the Quran: 'Say, He is Allah, the One. Allah is Eternal and Absolute. None is born of Him, nor is He born. And there is none like Him.' (Surah 112)

The vast and majestic universe with its flawless system clearly indicates that there is one creator and one supreme controller. The sun, the moon, and the galaxy obeys the same supreme Authority. The whole universe obeys the laws of this supreme power. There is complete co-operation and harmony in the system. Everything is nicely set in its place. No improvement can be suggested and no flaw detected. This superb and perfect combination of order and beauty is clear proof of the presence of an all-wise and all-Powerful Creator and Regulator.

Effect of Tawhid On Human Life

A believer in Tawhid surrenders himself completely to the will of Allah and becomes His true servant and subject. Allah has created all that is in the earth and the heavens for the service of mankind. When a person surrenders himself to Allah's commands, he gains control over all other creations of the universe.

It produces in the believer a high degree of self-respect and confidence. He knows that he depends on none but Allah for the fulfillment of His needs. He firmly believes that Allah alone has the power of providing all his requirements and no-one else has any power to do good or harm to him.

This belief makes a believer humble and modest. He is never arrogant or haughty. He is fully aware that everything on earth belongs to Allah and he gains control over the rest of the creation only by being a subject of Allah. He also knows very well that whatever he has, is from Allah. So, there is no reason to be proud and boastful.

Belief in Tawhid makes a believer dutiful and upright. The believer knows that he must carry out the commands of his creator to succeed in this life and in the life hereafter. This awareness keeps him away from neglecting his duties and from other sins.

It makes a believer contented. He does not become worried because he knows Allah will take care of all his needs if he is truly obedient.

It makes a person brave and courageous. It removes from his mind the fear of death or concern for safety. The believer knows that it is Allah who will cause death at the appointed time and none but He can harm the believer's safety. So, if he obeys Allah, he has nothing to worry about. He goes on doing his duty without any fear.

A believer in Tawhid consciously feels himself to be part of the whole universe. He is the best of all creation of Allah the Powerful Master of the whole universe. This belief enlarges his horizon and his outlook expands.

It produces in a believer strong determination, patience and perseverance. The believer becomes single minded and dedicates himself to seeking the pleasure of his creator.

The most important effect of the belief in - 'lailaha illal lah' - is that it makes a person obey and observe Allah's commands. A believer in Tawhid is sure that Allah knows and sees everything and he cannot escape Allah's ever-watchful eye for a single moment. In fact, Allah is nearer to him than his own jugular vein. So, a true believer does not commit a sin either secretly or in the darkness of night because he has the firm conviction that Allah sees everything all the time.

A believer in Tawhid seek the pleasure of Allah by making his belief and action go together. Belief without practice has no place in Islam.