For those who are still yet confused about this question, here is an excerpt from the site www.shariah.net explaining this profound yet most central concept of Islam.
THE ISLAAMIC BELIEF IN ALLAH
Belief in Allah is not confined to belief in the mere existence of a Creator. This belief necessitates the affirmation of Allah Ta’ala with all His Attributes in the way in which these are expounded in the Quraan and Hadith. A conception of Divine Being differing from the Islamic conception of Allah will not be belief in Allah Ta’ala.
ISLAAMIC CONCEPTION OF ALLAH
Allah Ta’ala is The Being who is Waajibul Wujood which means that His existence is by Himself, i.e. He is self-existent. His existence is absolutely independent of all things.
He is Waahid, i.e. He is absolute unity in that it is impossible for the concept of Waajibul Wujood to apply to any other being, it being exclusively His attribute.
He is Qadeem, i.e. there is no beginning for His existence. In other words, He is eternal. He is Qaadir (omnipotent –All Powerful); Hayy (Alive); Aleem (One of Knowledge); Baseer (the One who sees); Samee’ (the Hearer); Mureed (the one who wills). He is Mutakallim (one who speaks).
Allah Ta’ala has neither form or shape nor body. He does not subsist in any substratum. Nothing can contain Him, but He encompasses everything. He does not consist of particles or atoms. He has no constituent parts and He has no limits. He has no end.
He has no comparison and He has no properties and states such as color, taste, odor, coldness, moistness, dryness.
Time does not pass over Him. Nothing, down to the slightest detail, is beyond His knowledge and power. He is aware of all the details and particulars of every atom and of all things in creation.
He does not beget nor was he begotten.
He is the Sustainer, the Nourisher and the Controller of all creation. He is the Overseer, the Guard and the Protector of all and everything, from the greatest creation down to the minutest atom. His Control, Command and Knowledge extends simultaneously and perpetually over every single aspect and atom of
creation. Not a leaf blowing in the breeze, blows without His command, control and knowledge. All things operate by His direction.
He creates and annihilates according to His Will and Wisdom. All His actions are based on Wisdom –on infinite divine Wisdom and not human wisdom.
Creation can never comprehend Him.
He is beyond description and conception. No mind can ever conceive or comprehend Him. He is recognizable only by the manifestations of His Attributes.
He never tires nor does He sleep. He is above human qualities and free of all weaknesses and defects. His State is the same at all times. No change ever occurs Him. Nothing can act against or on Him. His Attributes are external. His Attributes are inseparable from Him.
Allah is Omnipotent. Nothing can curb or reduce His Power. His Promise is true and He will act in accordance with His promise, but His promise does not curtail His omnipotence. His promise does not reduce His Power. A promise by Allah does not mean that His power to act contrary to His promise is destroyed, e.g. Allah has created Jannat and Jahannum, if He so wills. He is the Creator and Master of all His creation. No one can question His actions. He is The Sovereign of all creation. As the Quraan says:
"He does as He pleases."
ALLAH, THE CREATOR OF ALL ACTIONS
All actions of creation are created by Allah Ta’ala, be such actions kufr or Imaan, worship or sin, obedience or disobedience. Man has no power of creation. Allah Ta’ala is the Sole Creator. However, Allah does not compel man to act. He has given man aql (intelligence) and has guided him with the mission of Risaalat (sending of Rasools to him) so that man can distinguish between truth and falsehood, virtue and vice. Allah has further granted man will (iraadah) to enable him to choose and act voluntarily in matters of truth and falsehood, obedience and disobedience.
Man in this world is on a journey of trial. Recompense in terms of his actions will be in the Aakhirah. Hence, when he uses his volition to act in any particular direction, allah Ta’ala does not restrain him, but creates the actions of his volitional choice, be such acts evil or virtuous, be they Kufr or Imaan.