But acknowledgement of Allah as the sole Sustainer of the world is not enough to become a Muslim. It is essential that this belief be substantiated with practice, i.e. to worship Allah, Alone, without invoking others for help. Pagans, particularly Arab infidels, acknowledge Allah as the sole Creator and Sustainer, but they can not be regarded as Muslims unless they substantiate this belief with practice, i.e., to worship Allah alone. If we look into the verses of the Holy Quran, we see that they call for the Oneness of Allah in worship. The various verses of the Quran tell us that unbelievers acknowledge Allah as the Only Sustainer of the universe, but their deeds do not conform to their belief. Therefore, they are admonished to confirm the oneness of Allah in their worship and in their deeds. Allah Almighty said, "O you people ! Adore your Guardian Lord Who Created you and those who came before you that you may have the chance to learn righteousness; Who has made the earth your couch, and the heavens your canopy : and sent down rain from the heavens; and brought forth there-with fruits for your sustenance; then set not up rivals unto Allah when you know (the truth)" (28) which was the first command to people in the Holy Quran by Allah, the Almighty.

We often find in the Holy Quran a call to the Oneness of Allah in worship. Simultaneously, the Holy Quran clarifies all doubts cast around this Oneness. In every chapter, virtually in every verse, this call for the Oneness of Allah is repeated. This is because the Holy Quran continuously informs its reader about Allah, His Names, His Attnbutes and His Characteristics, all reflecting his Oneness as the Creator and Sustainer, or when the Holy Quran calls people to worship Him alone and refrain from worshipping anything or anyone besides Him. This is the Oneness in worship. Then the Holy Quran informs people about Allah's grace in this life and His subsequent reward in the Hereafter for those who adhere to this Oneness totally. It also warns people about the punishment for idolaters in this world and the Hereafter. The Holy Quran also outlines the laws and commands of Allah, since Allah, alone, is the sole legislative power. This is the true manifestation of the Oneness of Allah.

This Oneness, with all its implications, is contained in the saying, "There is no god but Allah." It negates divine power from all and confirms it with Allah, the One and Only God. This, also, implies a "pledge of allegiance" to Allah and rejection of any partner to Him in any form. The Holy Qur an mentions the statement of Abraham (peace be upon him), "I do indeed clear myself of what you worship. I worship only Him who made me and He will certainly guide me." (29) Such has been the course of all the prophets who were sent by Allah. Allah the Almighty said "We assuredly sent amongst every people an apostle with the command, Serve Allah and eschew evil." (30) He, the Almighty also said "Whoever rejects evil and believes in Allah has grasped the most trustworthy hand-hold that never breaks". (31) Therefore, whoever has said "There is no god but Allah" has disavowed himself from worshipping anything other than Allah, and he has committed himself to worshipping Allah solely. In saying these words, he undertakes a pledge. "Then anyone who violates his oath, does so to the harm of his own soul. And anyone who fulfils what has been covenanted to Allah, Allah will soon grant his a great reward." (32)