Every language has one or more terms that are used in reference to God and sometimes to lesser deities. This is not the case with the word ‘Allah’. Allah is the personal name of the One True God. Nothing else can be called Allah. The term has no plural or gender. This shows its exclusivity when compared to the word ‘god’ which can be made plural, i.e. ‘gods’ or feminine, i.e. ‘goddess’. It is interesting to note that Allah is the personal name of God in Aramaic, the language of Jesus (p). The word Allah is a reflection of the unique concept that Islam associates with God. To a Muslim, Allah is the Almighty, Creator and Sustainer of the universe, who is similar to none and nothing is comparable to Him. The Prophet Muhammad (p) was asked by his contemporaries about Allah. The answer came directly from God Himself in the form of a short chapter of the Qur’an that is considered the essence of the Unity of God or the motto of monotheism. “Say: He is Allah, the One; Allah, the Eternal, Absolute; He begetteth not, nor is He begotten, and there is none like unto Him.” [Al-Qur’an 112:1-4]

Some non-Muslims allege that the concept of God in Islam is that of a stern and cruel God who demands to be obeyed fully. He is not loving and kind. Nothing can be farther from the truth than this allegation. It is enough to know that with the exception of one, each of the 114 chapters of the Qur’an begins with the verse: “In the Name of Allah, Most Gracious, Most Merciful” In one of the sayings of Prophet Muhammad (p) we are told: “God is more loving and kinder than a mother to her dear child.”

Besides being Merciful, God is Just too. Hence evildoers and sinners must have their share of punishment and the virtuous their rightful reward. Actually, God’s attribute of Mercy has full manifestation in His attribute of Justice. People suffering throughout their lives for His sake and people oppressing and exploiting other people all their lives should not receive similar treatment from their Lord. Expecting similar treatment for them will amount to negating the very belief in the accountability in the Hereafter and thereby negating all the incentives for a moral and virtuous life in this world.

The following verses from the Qur’an are very clear and straightforward:

“Verily, for the righteous are Gardens of delight in the Presence of their Lord. Shall we then treat the people of Faith like the people of Sin? What is the matter with you? How judge you?” [Al-Qur’an 68:34-36]

Islam rejects characterizing God in any human form or depicting him as favoring certain individuals or nations on the basis of wealth, power or race. He created the human beings as equals. They may distinguish themselves and earn His favor through virtue and piety alone.

The concept that God rested on the seventh day of creation, that God wrestled with one of His soldiers, 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.
The unique usage of Allah as the personal name of God is a reflection of Islam’s emphasis on the purity of the belief in God. This belief in the Unity of God, is the essence of the message of all the Prophets of God. Because of this, Islam considers associating any deity or personality with God as a grave sin that God will never forgive if the person dies without repenting.

The Creator must be of a different nature from the things created because if He is of the same nature as they are, He will be temporal and will therefore need a maker. It follows that nothing is like Him. If the maker is not temporal, then He must be eternal. But if he is eternal, He cannot be caused, and if nothing caused Him to come into existence, nothing outside Him causes Him to continue to exist, which means that He must be self-sufficient. And if He does not depend on anything for the continuance of His own existence, then this existence can have no end. The Creator is therefore eternal: 

“He is the First and the Last, the Evident and the Immanent: and He has full knowledge of all things.” [Al-Qur’an 57:3]

He is self-sufficient or self-subsistent or, to use a Qur’anic term, He is Al-Qayyum. The Creator does not create only in the sense of bringing things into existence. He also preserves them and takes them out of existence and is the ultimate cause of whatever happens to them.

“Allah is the Creator of all things, and He is the Guardian and Disposer of all affairs. To Him belong the keys of the heavens and the earth: and those who reject the Signs of Allah,- it is they who will be in loss.” [Al-Qur’an 39:62-63]

“There is no moving creature on earth but its sustenance dependeth on Allah: He knoweth the time and place of its definite abode and its temporary deposit: All is in a clear Record.” [Al-Qur’an 57:3]

GOD'S ATTRIBUTES

If the Creator is Eternal and Everlasting, then His attributes must also be Eternal and Everlasting. He should not lose any of His attributes nor acquire new ones. If this is so, then His attributes are absolute. Can there be more than one Creator with such absolute attributes? Can there be for example, two absolutely powerful Creators? A moment’s thought shows that this is not feasible.
The Qur’an summarizes this argument in the following verses:
“No son did Allah beget, nor is there any god along with Him: (if there were many gods), behold, each god would have taken away what he had created, and some would have lorded it over others! Glory to Allah! (He is free) from the (sort of) things they attribute to Him!”
[Al-Qur’an 23:91]

THE ONENESS OF GOD

The Qur’an reminds us of the falsity of all alleged gods. To the worshippers of man-made objects it asks: “Worship ye that which ye have (yourselves) carved? But Allah has created you and your handwork.”[Al-Qur’an 37:95-96]

“Say: ‘Do ye then take (for worship) protectors other than Him, such as have no power either for good or for harm to themselves?" [Al-Qur’an 13:16]

To the worshippers of heavenly bodies it cites the story of Abraham: “When the night covered him over, He saw a star: He said: ‘This is my Lord.’ But when it set, He said: ‘I love not those that set.’ When he saw the moon rising in splendor, he said: ‘This is my Lord.’ But when the moon set, He said: ‘unless my Lord guide me, I shall surely be among those who go astray.’ When he saw the sun rising in splendor, he said: ‘This is my Lord; this is the greatest (of all).’ But when the sun set, he said: ‘O my people! I am indeed free from your (guilt) of giving partners to Allah. For me, I have set my face, firmly and truly, towards Him Who created the heavens and the earth, and never shall I give partners to Allah." [Al-Qur’an 6:76-79]

THE BELIEVER'S ATTITUDE

In order to be a Muslim (i.e., to submit oneself to God), it is necessary to believe in the Oneness of God, in the sense of His being the only Creator, Preserver, Nourisher, etc. But this belief, later on called Tawhid Ar-Rububiyyah, is not enough. Many of the idolators knew and believed that only the Supreme God could do all this. To acquire Tawhid Ar-Rububiyyah one must add Tawhid Al-Uluhiyyah, i.e. one acknowledges the fact that it is God alone who deserves to be worshipped, and thus abstains from worshipping any other thing or being.

Having achieved this knowledge of the One True God, man should constantly have faith in Him, and should allow nothing to induce him to deny the truth. When true faith enters a person’s heart, it impacts the person’s outlook and behavior. The Prophet said, “Faith is that which resides firmly in the heart and which is proved by deeds”. One of the striking results of faith is the feeling of gratitude towards God, which could be said to be the essence of Ibada (worship). The feeling of gratitude is so important that anyone denying the Truth is called kafir, ‘one who is ungrateful.’ A believer loves, and is grateful to God for the bounties He bestowed upon him. He is aware of the fact that his good deeds are far from being commensurate with Divine favors, and therefore he is always anxious to please God. He remembers God often. The Qur’an promotes this feeling of gratitude by repeating the attributes of God very frequently.

“Allah is He, than Whom there is no other god; Who knows (all things) both secret and open; He, Most Gracious, Most Merciful. Allah is He, than Whom there is no other god; the Sovereign, the Holy One, the Source of Peace (and Perfection), the Guardian of Faith, the Preserver of Safety, the Exalted in Might, the Irresistible, the Supreme: Glory to Allah! (High is He) above the partners they attribute to Him. He is Allah, the Creator, the Evolver, the Bestower of Forms (or Colors). To Him belong the Most Beautiful Names: whatever is in the heavens and on earth, doth declare His Praises and Glory: and He is the Exalted in Might, the Wise.” [Al-Qur’an 59:22-24]

“Allah! There is no god but He, the Living, the Self-subsisting, Eternal. No slumber can seize Him nor sleep. His are all things in the heavens and on earth. Who is there can intercede in His presence except as He permitteth? He knoweth what (appeareth to His creatures as) before or after or behind them. Nor shall they compass aught of His knowledge except as He willeth. His Throne doth extend over the heavens and the earth, and He feeleth no fatigue in guarding and preserving them for He is the Most High, the Supreme (in glory).” [Al-Qur’an 2:255]

“O People of the Book! Commit no excesses in your religion: Nor say of Allah aught but the truth. Christ Jesus the son of Mary was (no more than) a messenger of Allah, and His Word, which He bestowed on Mary, and a spirit proceeding from Him: so believe in Allah and His messengers. Say not “Trinity” : desist: it will be better for you: for Allah is one Allah: Glory be to Him: (far exalted is He) above having a son. To Him belong all things in the heavens and on earth. And enough is Allah as a Disposer of affairs.” [Al-Qur’an 4:171]
 

[Source : WAMY2 Series on Islam]
1 (p) here stands for “peace be upon him”
2 World Assembly of Muslim Youth