Bismillahirohmaneerohim (in the name of Allah, the Most Merciful, the Most Compassionate)
Allah is generally known as God for muslims. Ilah is god in arabic language and Allah is "the God" in arabic. Therefore, I would like to clarify that Allah is not a Malay word. The Malay word for god is tuhan. Anyway, my main topic is to discuss the concept of Allah. Since the word is going to be widely used, it is important to know the concept of Allah in Islam.
Firstly, Allah is one.
"Say: He, Allah, is One." (Surah al-ikhlas verse 1)
"And your God is One God, there is no God but He; the Most Merciful, the Most Compassionate!" (Surah al-baqarah verse 163)
"Had there been in them any gods in the heavens and the earth apart from Allah, the order of both the heavens and the earth would have gone to ruins. Glory be to Allah, the Lord of the Throne, Who is far above their descriptions of Him." (Surah al-anbiya verse 22)
The verses above states that Allah is one. Surah al-anbiya states the consequence if there are many gods. I would also like to think in a different perspective that if there were many gods, wouldn't there be a conflict of interest? For example god A gives instructions to do things which contradicts with god B. Which god would the person serves to? If a person were to choose one instruction, why is that god superior over another? It is simple to grasp that god is one, and in my opinion it exposes the superiority of the oness of god to create everything. If there were many gods (god of wind, god of rain), it shows the limitness of the power where "god" can only handle certain function. Therefore, oness shows the unlimited power that Allah has.
"(He is) The Creator of the Heavens and the earth: He has made for you pairs from among yourselves, and pairs among cattle: by this means does He multiply you: there is nothing like unto Him, and He is the One that hears and sees (all things)." (surah as-shura verse 11)
Why is it important to understand that there is nothing like unto Him? I have read some criticism about "Muhammad's god represents the concept of existing blankness, an empty intellect". I will attempt to show that this is not the case.
If god is something similar to a thing that we know, we may know/assume/estimate gods capabilities because of the similarities. It is always in the nature of human beings to assume and this would be insulting (to god) to assume limitation to gods capabilities. When a person have knowledge of the capabilities, a person may know its advantages and disadvantages therefore the element of superiority is gone. Allah is beyond imagination, our knowledge are too little to put an image to Allah. Secondly, if god is similar to something, a person may get confuse onto what he/she should worship/give thanks/pray to. Therefore it is important to know that Allah is unique and cannot be imaged with the limited power of our brain.
However, I have encountered a muslim brother who says "man should be a reflection image of god". From my understanding the brother is being heavily influenced by the books that he has read. This is clearly is not from the Islamic doctrine where "a man should be a reflection image of god". The rationale of "man should be a reflection image of god" is because apparently god is so "proud" of himself that god would like to see his best creation/masterpiece in his own image. Why does this have to be the case? Is it necessary for we humans to create a masterpiece in our own image? Do we build houses in an image of humans? Do we build cars (Ferrari, Bugatti) in the image of humans? Why are houses and cars shaped in such manner? Houses should serve its purpose to give a shelter and cars should serve its purpose for transportation. So human are designed in such a manner to serve its purpose, which is to worship Allah, to help each other and etc. Would a person wants his/her image to be something that has limited function? For example does a person wants his/her image to be a ceiling fan? A ceiling fan that can only serve its function just to circulate air/wind? That would be insulting for a person to be/to use its image a ceiling fan (which is not intellectual and not necessarily productive as human). So why should Allah look like a human (which has limited functions compared to Allah)?
Why do creatures or animals look different? Firstly so that we could differentiate and easily identified. Secondly, so that one could know their functions. For example, a cow are easily identified and a person would know that a cow can provide milk and etc. So, if "god" looks like a human or human looks like a "god", it is hard for us to notice "god" in a crowd of people and god would not get the respect. Nothing would be special if we humans and god look alike.
Some would like to know "when" did god exist. In accordance to "when" there is the element of time. We base our time on the circulation of earth, sun, moon and etc. If these things were not created, how do we calculate time? Another thing is, why is time so important? It is because we humans are mortals which life will come to an end. If we humans do not die, is time really that important? In my personal opinion, time would not be important to me if I am immortal because I can do anything at anytime (no restrictions) and I do not feel I have wasted anything (time) because time is infinite. But the reality is, we are mortals and therefore are bound in "time". It is because we know our life will come to an end which makes the element of time more important or precious. My point here is that, Allah has created everything in the universe including the circulation of earth, sun, moon and etc, so why should "time" be applicable to Him? Allah the Creator of every single thing has to be superior and if god were to be a mortal, who would succeed to run the universe after god's death? In my opinion it doesn't make sense if Allah the Almighty is to be binded in his own creation (time). Even though it is obvious we know there's a limited lifetime (time), most of us do not consider the usage of that "time". So, within this limited time, do we think/worship Him enough?
"And call not, besides Allah, on another god. There is no god but He. Everything (that exists) will perish except His own Face. To Him belongs the Command, and to Him will ye (all) be brought back." (surah al-Qasas verse 88)
"He cannot be questioned concerning what He does while they shall be questioned." (Surah al-anbiyaa verse 23)
All things are destined in the end (our time) to the One Who has facilitated their being what they are, the One Who cannot be explained; therefore, the attempt to analyse Him, His Attributes, and His actions, is simply impossible. We should always remind ourselves that we are "limited" and be humble to the One and Only Allah.