"A similar (favor have ye already received) in that We have sent among you a Messenger of your own, rehearsing to you Our Signs, and purifying you, and instructing you in Scripture and Wisdom, and in new knowledge." (Surah al-Baqara (2): 151)
This verse summarizes the reason for Prophet Muhammad (and inadvertently all other prophets) being sent [to mankind] and his mission. In the verse, Prophet Muhammad's (pbuh) responsibility as a messenger is explained through the words" reading our verses"; his responsibility as a guide is explained cumulatively through phrases such as "the one who reads our verses," and in relation to his role as a messenger he is said to be "purifying you," and finally his role as a leader and teacher are explained as "the one who teaches what we don't know."
Only prophets can create a balance between our material and spiritual sides, both of which we cannot give up on as they represent two separate realms of our lives as humans. There may be those among humans who have distanced themselves from their material lives and have an advanced level of spirituality; however, finding the balance between this world and the hereafter, without abandoning either is the greatest sign of perfection and this ability has only been displayed in the life of the last prophet.
It is also stated that our Prophet was sent as a mercy to mankind in the Holy Qur'an. This reflects that just as Islam and the Qur'an are universal, the exemplary status of prophets is also universal. Because he did not stop of relaying the Qur'an to humans, he displayed for the believers, through his own life, how to apply the principals of belief, manners, worship and social life -- that are ordered in the Qur'an -- into everyday life.
Humans sometimes hold the presumption that behavioral virtues are utopic traits. Particularly during periods in which lack of morality have become normalized to the extent that this situation is rampant, pessimism can reach an all time peak. At this point, examining the life of Prophet Muhammad, which has been narrated to us in detail, in addition to the stories of the prophets shared in the Holy Qur'an, will work to cure us of our pessimism. Familiarizing ourselves with his lofty moral being, as well as his traits such as generosity, courage, honor, respect, humility and dignity will provide us with real life examples at a level which we cannot even imagine. And thus we will have witnessed how these principals can be applied under real life conditions instead of listening to abstract advice on matters. For this reason, knowing him, learning and understanding his Sunnah -- his sayings and actions -- will allow us to understand that the moral perfection of mankind is in fact possible. It is for this reason that his prophecy is universal. Everyone who lives in this world, who struggles to maintain a righteous path in their morals, beliefs, worships and social life, needs his guidance.
Why is it that humanity must learn and follow Prophet Muhammad's life in addition to all of the reasons which have been listed? Because:
1. Unless a Muslim follows the path which is set by the Messenger sent by Allah, they cannot even be Muslim.
2. The principals which he taught were immediately written down and passed down to us through reliable methods. There is not another person among the great thinkers in history whose information about their personal lives has survived until today in such detail and reliability as that of Prophet Muhammad.
3. The path of prophets whom Allah (swt) has sent throughout history can only become apparent through knowing Prophet Muhammad. Because the lives of prophets before him has been overshadowed by legends in addition to not being recorded in history.
4. Prophet Muhammad emphasized the universality of his message ever since he began delivering his message; he never stated that this was a local message and never limited himself by a certain nation or a time frame. He never differentiated among people based on material status (race, lineage, wealth etc.)
5. One of the most important signs of the universality of Prophet Muhammad's prophecy was that he did not address people who were angelic alone. The Qur'an and the Sunnah address the majority of average people and thus show people how to attain perfection. For this reason, the road leading to perfection in Islam has not been limited by divine activities alone; quite the contrary, it includes everything from trade to childcare; marriage to familial relations, in short all of our worldly and social lives have been linked to religion and included as part of the divine path.
"Ye have indeed in the Messenger of Allah a beautiful pattern (of conduct) for any one whose hope is in Allah and the Final Day, and who engages much in the praise of Allah." (Surah Al-Ahzab (33): 21)
The character and moral make-up of a person can be best understood by those who are closest to that person. For this reason, the testification of those who are close to us are more accurate than those who know of us in a single area of our social lives. The sentences uttered by our Prophet by those closest to Prophet Muhammad, his family, relatives, friends, neighbors and work friends, always noted and admiration for him. Those who accepted the truth of his message were most affected by his honesty when doing so. Actually, even those who harbored animosity towards him could not contain themselves from testifying positively on his character.
Despite all of his lofty qualities, if Prophet Muhammad had not been made the last prophet chosen by Allah, then for us he would have simply been one of the many exceptional people in history. Meaning when we respect his good behavior, personality and the two guides which he left for us: the Qur'an and the Sunnah, we are actually respecting the choice of Allah. And those who have remained indifferent to him or his message throughout history, starting from the Jews of Medina and the Christians who met with the prophet and brushed with his calling, are those who have also remained indifferent to this choice [of Allah] as well.
The person who is bringing a message is undoubtedly important; however, what is more important and binding is the authority sending the message. The respect and trust we have in the authority determines our behavior against the messenger. Thus our stance before Prophet Muhammad, who is the last link in the chain of prophecy and the harbinger of the prophets before him, is as such. Even if we are not able to hastily apply his calling to our daily lives due to cultural and personal habits, refraining from opposing him, engaging in enmity against him, not denying his divine message are the minimal requirements of our servitude to Allah the Almighty.