Bearing in mind Muhammad's commission (P.B.U.H.) to the whole of mankind as a prophet and a messenger, it will incur that his principal mission would be: the demonstration of Allah's religion and the interpretation of His descended holy Quran through his honorable legal deeds which we have confirmed their being a practical replica of what the verses of the Quran meant comprehensively and in detail.

But this does not prevent the lucky people from meeting their secular and religious needs altogether as being a necessity for them to contain both jointly to a degree which can make them appreciate what is religious and what is a worldly pleasure.

And this, in fact, necessitated the one who wants to harmonize in practice between what is spiritual and what is practical in common life and rather necessitated to be awarded the required acceptability which could enable him to organize his affairs in a way that would liquidate the rising conflict of interests and the inevitability of intersection between the people. 

This acceptability is but a state of purification and a heavenly qualitative choice in selecting the one who is the best among them and the most benevolent through a number of qualities such as being endowed with: good manners, moral values and normal behavior and the traits of his family which should accord with what is nowadays called: the instinctive and hereditary aptitude for rendering those values and morals acceptable in addition to other praiseworthy merits and traits.
Based on such criteria, the Prophet, has been the chosen, the most preferable one to whom Allah, the Almighty, has given the right to administer the people and organize their living affairs, beginning with the necessity of paying him absolute obedience by considering-his obedience-as obedience to Allah and this fact is confirmed in the holy Quran: 

"He who obeys the Messenger (Muhammad) has indeed obeyed Allah, but he who turns away, then we have not sent you (O Muhammad) as a watcher over them." (Al-Nisa: 80) that is, for he doesn't speak out of his passion and verily, his speech is but the speech of Allah, the Almighty: "Nor does he speak of (his own) desire. It is only a Revelation revealed."(Al-Najm: 3- 4). 
And since the noble Prophet (P.B.U.H.) has been the Seal of all prophets, their purest and their most refined character in reforming-mankind-the whole of mankind-and that his legislature is the most permanent and the most durable of all religions, it, required to be, owing to that, an ideal pattern-a typical model in application-that is to say: a Guiding Hand-which can push the world forward towards ways happiness in both abodes via his application of the heavenly theses on earth amongst which is the building up of a Muslim Society in accordance with highly constitutional bonds responding to what was descended in his holy Quran at a time when the noble Prophet (P.B.U.H.) was the Messenger of Allah and His warner to the whole of the worlds, went on establishing-by order of his Lord-a spiritual building for them in a disciplined manner through constructing a society whose government stems from divine rules and heavenly judgements-other than that which they used to refer to during the pre-Islamic rule when conflicts were steadily arising between the tribes; therefore, he became their leader, their chieftain and their top guardian especially, his words, deeds an decisions were all descending from Allah, the Glorified even though some of their affairs, related to their domestic affairs or perhaps, their practical life items.
For all this, he deserved to be their supreme authority in terms of their secular life and the life of the Hereafter altogether. 

The Prophet Muhammad (P.B.U.H.) started with the process of changing the society and reforming its defective conditions in the same manner that Allah, the Almighty has started with him.  

Allah has given him power to rehabilitate them by qualifying him to undertake the task successfully, beginning with making them behave properly and organize their living conditions to get to managing them as a society-having a government, an army and a political system because of his being the higher executive authority and the one who could draw up to them the general features of their political affairs, provide for them its requirements and finally, explain to them all that which can transfer them from nomad life into a civilized environment. 

This indeed totally differs from the nomadic and backward society amidst an absolute acceptance of the overwhelming masses of the Muslims who ought to put in mind his being commissioned by the Lord, the Exalted, to them in addition to his infallibility which necessitates that all his theses revolve around the circle of his being absolutely right and that people accept them as totally right and be taken for granted.
On this basis, people ought to have been content with him and ought to have given a pledge of allegiance to him to the extent that he be more favorable than themselves, particularly, after being trusted on their religion and that he is more worthy of being trusted on their worldly life in its spectra of dimensions as well. 

Preferentiality Exposes Itself
Verily, Allah's selectivity with regard to His Prophet's commission (P.B.U.H.) to people as a prophet and a messenger has been owing to his being the most understanding, the most preferable, the most pious and the most daring character together with other attributes: some of which are associated with the laws of heritage, progeny and the purity of birth; without which, he will lose the justification of heading the spiritual and practical chieftainship over the people.

Since Muhammad, the Prophet (P.B.U.H.) was the most preferable one, it would be illogical to prefer the "favorable" one over the "most favorable" one and the "perfect" one over the "most perfect" lest the proof loses its power and impact in the eyes of all especially when we know that his acceptance demands the approval of the whole human masses as that requires the availability of the preferable characteristics and granting the priority of his status, especially the overwhelming majority of the people who are unable to appoint the most preferable one at the time when other human groups convene joint covenants through which they can establish peaceful coexisting conditions via their search for (the most preferable one) and here comes the Divine Fairness which provides all that which makes Muhammad (P.B.U.H.)  that most preferable person in the whole human society…the whole human society.
And there may happen to be some positive qualities in one person, other than the person of the Prophet (P.B.U.H.) not exclusively restricted to him as in someone who is characterized as being qualified to manage a Muslim Society as far as that living system of society is concerned financially, economically and socially and perhaps religiously as well.

But there can be no guarantee as it can maintain him from the pitfalls of prestige and the recurrent people's need for him in all of their requirements in a way that it can grow in him the sense of "egoism" but that which is termed as "infallibility" with which Allah, the Almighty, has kept him safe from slips and wrongs and errors and enriched him with protective valves which could grant him the preservation of valid attitudes and rather increased in them their trust him and raised in them the tide of their acceptance of him.

Building upon this big advantage of "preferentiality", Muhammad (P.B.U.H.) has abundantly got more than one authority in hand (with no need to separate the three common authorities as "separation" has a common phenomenon as it occurs now in man-made systems) but rather remained acceptable by the people as a result of the availability of the guarantees which keep safe and secure all these properties which he enjoys as an infallible prophet and as a leader containing all the details of the heavenly constitution" the holy Quran" with all its sub-titles, origins and principles that relate to it especially, those which have lots to do with the rights and duties of the people; besides his ability to convince people about the necessity of showing absolute obedience to the tasks of which they are in charge as well as paying due respect to their rights and organizing their interests via his honorable common tools of the so-called " Al-Sunna Al-Nabawiya." i.e. the prophetic legal deeds.