Man must believe, whether in the true God or in any false deity, which he might call god or something else. This deity could be a tree, a star in the sky, a woman, one's boss at work, a scientific theory, or it could even be some personal whim. However, he must have faith in something that he could follow and sanctify and refer to in his life course, and he might even die for its sake. This is what we call "worship", and worshiping the true God is what sets man free from being a slave to others and to the society.
The true God is the Creator and worshiping other than the true God implies the claim that they are deities. The God must be a creator and the proof of his being a creator must be either by witnessing what he has created in the universe or by revelation from God Who is proven to be a Creator. So, if this claim has no proof to support it, neither from the creation of the witnessed universe nor from the words of the Creator, then such deities are definitely false deities.
It is noticed that in hard times man tries to focus on a single truth and resorts to only one God. Science has proven the unity of matter and the unity of the universal system through examining the manifestations and phenomena of the universe, and through the resemblance and similarity that exist in it.
Let us imagine what would happen to the children of the same family if their parents disagree on an important issue, and how their disagreement would lead to the loss of their children and the destruction of their future. Similarly, what would be the case if two gods or more rule the Universe?!
Allah Almighty said:
{If there had been gods besides Allah in the heavens and earth, both realms would have fallen in disorder. Glory be to Allah – Lord of the Throne – far above what they ascribe [to Him].} [1] [Surat al-Anbiyā’: 22]
Moreover,
the existence of the creator must precede the existence of time, place, and energy. Accordingly, nature cannot be the cause leading to the creation of the universe because nature itself is made up of time, place, and energy. Therefore, this cause must have existed before nature.
In addition, the creator must be a vanquisher, i.e., He must possess authority over everything.
All matters must belong to Him so that He could issue His command of initiating the creation.
He must possess complete knowledge about everything, i.e., He must fully know everything.
He must be one and only one and must need no others besides Himself. He must have no need to be embodied in the form of any of His creatures. He needs no wife and no progeny in all cases because He must combine all the attitudes of perfection.
He must be wise and must do nothing except for a specific wisdom.
He must be just and his justice entails reward and punishment. He must be connected with humans, otherwise he would not be God if He creates them and abandons them. For this reason, He sends them messengers to show them the way and to convey His law. Those who follow the way are entitled to receive His reward, while those who deviate from it deserve His punishment.