Imam al Juwaini, a renowned Muslim theologian, said that the true nature of faith is true belief in God. A believer is then a person who truly has faith in God. The profession of true belief, in reality, is an interior discourse but it does not exist except with knowledge. It is rather absurd to say that a man acknowledges God but does not believe in Him.
The unanimous agreement of scholars is that all acts of worship have to be proceeded by faith. In this way, acts of obedience are seen as faith. God says, "God will not cause your faith to be lost" (Quran 2:143). In this verse, "faith" here namely means prayers made in the direction of Jerusalem. This could be confirmed by the Prophet's words in which he says,

It is narrated on the authority of Abu Huraira that the Messenger of God (may peace and blessings be upon him) said:

“Faith has over seventy branches or over sixty branches, the most excellent of which is the declaration that there is no god but Allah, and the humblest of which is the removal of what is injurious from the path; and modesty is the branch of faith.”

Once a person hits puberty, he needs to start reasoning which is a reflection with the purpose of seeking to establish either certain knowledge or the preponderance of conviction. Reasoning is then divided into two: the correct and the false. Correct reasoning is what leads to discovering the method by which a proof is proven and the false is what precludes it. Reasoning can be defective through deviating from the rules of proof from the start or might become false even though begun on proper basis because of an extraneous factor that intervenes. Sound reasoning provides intellectual surety of the certainty of the knowledge of the object. Sound reasoning reveals to the reasoned the manner by which a proof entails knowledge of the thing proven. When reasoning is interrupted by the occurrence of a fallacy, it becomes defective.
By using human reasoning we can say that the imposition of religious obligation is a "trust" that no creatures other than humans can bear. God says, "We offered the Trust to the heavens and the earth and the mountains and they refused to bear it and shrunk from it but man took it up…" (Quran 33:72). The "trust" or the "amana" is the assumption of the commitment to obey God's commands which exposed them to the benefit of reward or the risk of punishment on the basis of obedience and disobedience. When the Trust was offered to the heavens, earth etc…, their natural refusal was due to their incapacities and the absence of suitability to bear such trust. By man's taking it up is meant his fitness and capacity for it.
Also taking up the Trust by man means that he possesses both knowledge and justice; which are qualities that are not found in other creatures. Beings other than man are either knowing and just, untouched by sin and ignorance such as the angels, or they are neither just nor knowing neither is it their place to acquire these qualities such as is the case for animals. Therefore, the only one suited for the imposition of religious obligations and having the capacity for it is the one who has the potential for perfection and not the actuality.
If we take a closer look at the condition of the angels in their transcendence, they are neither disturbed by any state rising up from the deficiency of the animal force such as hunger, fear, thirst or sorrow nor by its excesses such as lust, anger and vanity. Moreover, they are not preoccupied with nutrition and growth and what pertains to it. They remain exclusively occupied with waiting for what shall come to them from above. They are totally dispatched to undertake whatever is required from them. This means that angels are utterly oblivious of their own volition and only subsist through the purpose of what is above them.
As for the condition of the beasts, they are stained by sensual forms, continuously infatuated with natural needs, totally absorbed in them. They are not provoked to do anything except by animalistic provocations traceable to a concrete benefit, they abandon themselves totally to the demands of their nature.
God created and deposited in man two forces. One is an angelic force which branches out from the emanation of the spirit particularized for man into the natural spirit. The second is an animalistic force branching out from the animating soul common to all animals. The contention and competition which occurs between these two forces are the constructive forces of the human being. The former force pulls toward the high and the latter toward the low.
Therefore, religious obligation is one of the requirements of the human species due to their capacity and natural ability. Based on this, God rewards humans for seeking their potential capacity and angelic level and forbids man's engrossment in the animalistic and will punish him for it.
Man's natural capacity and his potential for perfection comes from his innate properties which distinguish man from the rest of animals such as rationality, understanding speech and the derivation of acquired sciences from the ordering of axiomatic principles or from experience, induction and intuition. Humans are concerned with matters which their reason judges commendable although they did not find these out through sense perceptions or imagination, such as the refinement of the soul and the subjugation of regions under their control. These ideas which govern human thinking is embedded through the natural disposition of man which requires that his intelligence dominate his heart and that his heart dominate his lower soul.
The natural disposition of man with his sense perception, movement and receptivity to the revelations of natural disposition and natural sciences along with his intellect enabled man to produce, plant, cultivate, and engage in trade and social transactions.
The common ideas which human beings have towards establishing kingdoms, political arrangements and societal collective character are driven from outer properties and outer regulations connected to man's animal force and the support of his livelihood.
When it comes to his angelic force, man's intellect sets him apart from other species of animals as he has a higher level of understanding and discernment which enables him to pose inquiries into the cause of his coming into being, the ultimate purpose of his stay and his final destination after death. Through his inquisitive mind and thorough observation, he becomes aware of the well-organized, highly systemized order of the universe with its infinite marvels. This leads him to the awareness of God's existence and therefore humbles himself before the One.
The intelligent mind of man which deduced the existence of God, has imprinted on his soul an intellectual supplication commensurate with the supplication of his physical state. An additional human property is that there are those among the human species who can arrive at the source of rational knowledge and who learn from it through revelation, intuition or dreams. People detect with their rational faculty the human-sources of guidance and follow them and those who arrive at the rational knowledge and God blesses them with divine guidance become beacons of light and are called Prophets. The prophets are those whose degree far surpasses the bounds of the bestial attributes so they are characterized with humbleness, generosity, kindness, purity, justice and magnanimity. These are glimmerings of God's divine attributes and the higher the spiritual elevation of the human being, the closer he reaches his full potential capacity of reaching a state of approximation to God.

The reason behind man's capacity to reach his full potential is because of some special traits which set him apart from the rest of the animals. These traits are:
1- The preponderance of the intellectual traits which allow the human being to enjoy exercising his skills in deriving the means for establishing civilizations and for benefitting the human order. In addition, this intellectual trait prepares him for seeking knowledge of the unseen by way of divine inspiration and revelation.
2- The proficiency of the practical faculty which paves the way for God's knowledge, love and trust take practical forms. Actions therefore are divided into five categories: the required, the recommended, the neutral, the reprehensible and the forbidden. The divine law also introduces the premises which clarify the stages of progress (ihsan).
Therefore, human beings are the only creatures who have the intellectual ability to gain knowledge of God's existence through reasoning. They are the only creation alongside Jinn with free will to submit their bodies in worship and surrender their hearts in love to create a beautiful painting which represents the ultimate freedom of man in submitting to God willingly and freely. This makes religious obligations a beautiful and elaborate expression of human freedom in knowing, loving and worshipping their Lord motivated by their inner temperament and natural predisposition that provides them with the fuel of reaching their full spiritual potential and become a real manifestation of God's divine names and attributes.