Nobody knows Allah, as He deserves to be known except Allah Himself.

Imam `Ali says the following:

One who assigns conditions to Him does not believe in His Oneness, nor does one who likens Him to anything grasp the reality about Him. One who illustrates an example for Him does not revere Him. One who points at Him and imagines Him does not know the meaning of His Lordship. Anything known by itself is a created thing, and everything that exists by virtue of other things is the effect thereof. He does things but not with the help of instruments. He assigns measures but not with the faculty of thinking. He is rich but not by acquisition. Time does not keep company with Him, nor does He seek help from any means. His Being precedes time. His Existence precedes non-existence, and His eternity precedes beginning. By creating the senses, it is known that He does not have the same. By comparing antitheses, it is known that He has no antithesis, and by striking similarities between things, it is known that there is nothing similar to Him. He has made light the contrary of darkness, brightness the opposite of dimness, dryness the opposite of moisture, and heat the opposite of coolness. He causes harmony among opposites. He fuses together diverse things; He brings closer what is remote and distances what is joined together. He is not confined to limits, nor computed by figures. Matters are attracted to one another, and parts point out to what is similar to them; the word "since" disproves their eternity, and possibility disproves their perpetuity, while certain means keep them distant from perfection. Through them does the Creator manifest Himself to the intellect, and by them is He veiled from vision. Stillness and motion do not apply to Him; how can anything that He causes to have any effect on Him, and how can anything which He has created revert in its effect unto Him? On the other hand, how can anything have an impact upon Him while He Himself brought it to being? Had it not been so, He would have become subject to diversity, His Being would have become divisible (into parts), and His reality would have been prevented from being Eternal. Had He had a front, He would have had a rear! He would have needed to be completed had there been any shortage in Him. In that case, characteristics of His creatures would have appeared in Him, and He would have become a sign (leading to other objects) instead of the latter leading to Him. Through the might of His effectiveness is He distanced above being affected by things. Neither change nor extinction affects Him. He has not begotten anyone lest He should be said as having been Himself born. He has not been begotten lest He should have been confined to limits. He is too sublime to have sons, too pure to take women. Imagination cannot reach Him to assess Him. Comprehension cannot conceive Him and fancy a shape for Him. Senses do not perceive Him to probe Him. Hands cannot touch Him to feel Him. He does not change into any condition. He does not pass from one stage to another. Nights and days do not age Him. Light and darkness do not alter Him. It cannot be said that He has a limb or extremity, an end or expiration, nor do things control Him to raise or lower Him, nor does anything support Him to bend Him or keep Him erect. He is not inside things or outside them. He conveys news, but not with the tongue or voice. He listens, but not with ear holes or organs of hearing. He speaks but does not utter words. He remembers but does not memorize. He determines but not by exercising His mind. He loves and approves without sentiments. He hates and feels angry without any painstaking. When He intends to create a thing, He says to it "Be" and it is, but not through a voice, that strikes (the ears). His speech is a manifestation of what He has created. His peer never existed before, nor is He regarded as old; otherwise, He would have become a second Allah. It cannot be said that He came into being after He had not been in existence because in that case the effects of creation would have been reflected on Him, and there would have remained no difference between them and Him, and He would have no distinction over them. Thus, the Creator and the created would have become equal, and the Initiator and the initiated would have been on the same level. He created creation without any model made by someone else, and He did not secure the assistance of any among His creation for creating. He created the earth and controlled it without having to hold it, retained it without having to support it, making it stand without poles, raising it without pillars, protecting it against bending or curving, defending it against crumbling or fragmenting. He fixed mountains on it like pegs, solidified its rocks, caused its streams to flow, and expanded its valleys. Whatever He made did not suffer any flaw, and whatever He strengthened did not permit any weakness. He manifests Himself over the earth through His authority and greatness. He is aware of what there is inside it through His knowledge and understanding. He has power over everything on earth by virtue of His sublimity and dignity. Nothing on earth that He asks defies Him, nor does it oppose Him to overpower Him. He is not in need of anyone to feed Him. All things bow down to Him and are humble before His greatness. They cannot flee away from His authority to someone else in order to escape His benefit or harm. There is no parallel for Him who may match Him, and none is like Him to equal Him. He will destroy the earth after its existence, until all that exists on it will become non-existent. However, the extinction of the world after its creation is no stranger than its formation and invention the first time. How could it be? Even if all the beings on earth, be they birds or beasts, cattle or pasture herds, of different origins and species, clever or not so clever nations, all jointly combine efforts to create even a mosquito, they will not be able to bring it into being nor understand the means to its creation. Their wits are bewildered and they are aimlessly wandering. Their powers fall short and they fail, returning disappointed and worn out, realizing that they are defeated, admitting their inability to produce it. They will also realize that they are too weak (even) to destroy it. Surely, after the extinction of the world, Allah the Glorified will remain alone with nothing else besides Him. He will be, after its extinction, as He was before then: without time or place, a moment or a period. Age and time will not then exist, and years and hours will disappear. There will be nothing except Allah, the One, and the Omnipotent. To Him is the return of all matters. The initial creation of all matters was never within the power of the latter, and the prevention of their own extinction was never within their reach. Had they had the power to prevent such extinction, they would have existed forever. When He created any part of this world, its making did not cause Him any difficulty, and the creation of anything, which He created and formed, did not exhaust Him. He did not create it to enhance His authority, nor did He do so for fear of any loss or harm, nor to seek help against an overwhelming foe, nor to guard against any avenging opponent, nor for the extension of His domain, nor for boasting of it before a partner, nor because of His feeling of loneliness and desire to seek company. Then, after its creation, He will destroy it not because of any worry that overcomes Him neither in maintaining and administering it, nor for any pleasure that will accrue to Him, nor for the cumbersomeness of anything over Him. The prolongation of its existence does not wear Him out to induce Him to its quick destruction. However, Allah, the Glorified One, has maintained it with His kindness, kept it intact with His command, and perfected it with His might. Then, after its destruction, He will bring it back to being again not for any need of His own for it, nor to seek the assistance of anything in it, nor to change the condition of loneliness to that of company, nor from ignorance to knowledge, nor from want and need to independence and plentitude, nor from disgrace and lowliness to honor and prestige.