Historians have clearly discerned in all dimensions of his person great spiritual energy and power, together with all the other qualities that are fitting in a great leader sent by heaven.
No researcher or scholar can claim that the Prophet, upon whom be peace, fell prey at any point in his life to moral or spiritual deviation or to nervous excitement. Although the characteristics of the Prophet of Islam are more clearly and fully known than those of other people who have left their mark on history, in the near or distant past, history cannot point to the slightest rebelliousness, ill-temper or evil conduct on his part, nor even to a single error or sin.
The remarkable life of the exalted Prophet of Islam is clearly and completely known in all of its aspects: the period before his birth, his infancy, his youth, his moral characteristics, his travels, his marriages, his conduct in war and peace.
Recorded history bears witness that the slightest trace of corrupt belief cannot be found to have clouded his brilliant visage. Although he had no access to any form of instruction, he had no connection with the Age of Ignorance surrounding him, and vice was never able to take root in him.
The creedal environment in which he grew up was a compound of polytheism and idolatry, as is shown by the strong resistance of the Arabs to his summons to monotheism. The entirety of his early life was spent in the midst of an ignorant, evil-living and oppressive people and he never left that environment before the beginning of his mission with the exception of two journeys outside the Arabian Peninsula, once in childhood, in the company of Abu Talib, in the early part of the second decade of his life, and once in his mid-thirties when he went trading with the goods of Khadijah. Nonetheless, we find not the least affinity between his personality and the society in which he lived.
The aspect of his personality that was particularly valuable in that corrupt and polluted environment was his honesty, trustworthiness and unfailing sense of justice, together with his hostility to all the forms of humiliation from which mankind was suffering.
Muhammad, upon whom be peace, captivated the hearts of his contemporaries with his nobility of character and his kindness toward the weak and the afflicted. Friend and enemy are agreed that none of the men of his age even approached him in the perfection of his attributes and spiritual characteristics.
For example, Zayd b. Haritha, who had been separated from his family at an early age and was given by Khadijah to the most Noble Messenger, upon whom be peace, as a slave, spent his entire life with him. After a time, Zayd’s father came looking for him in order to reclaim him. Now Zayd had been emancipated by the Prophet, upon whom be peace, but he was still a slave to the love the greatness and the splendor of the Prophet, and captivated by the excellence of his conduct and behavior. So although he was free to return to his family, he preferred to remain with the Prophet and serve him.
Eloquence and profundity of speech, fairness in judging, superior intelligence and perception, heavenly disposition and brilliance of thought – all these were abundantly evident in the being of this great personage. They shone forth in all the varied scenes of his life, and he so lived that years before the beginning of his prophetic mission, he was awarded the title “amin”, ‘trustworthy’, an eloquent description of his whole mode of conduct. During one of the religious festivals of the Quraysh, an incident occurred that struck a blow at the rule of the idolators. In the middle of the festival, while the people were gathered around an idol and rubbing their foreheads in the dust in front of it, a few clear-minded and pure-hearted people such as Waraqa b. Nawfal, who were distressed by the corruption prevailing in Mecca, began to discuss the situation. They asked themselves how much longer it could continue and when the time of delivery would come. Why were those people prostrating in front of objects, and why had they distorted the religion of their forefather Abraham?
One of the things they said was this: “What is that piece of stone around which they are walking? A thing that neither sees nor hears, that does not breathe, that can give no benefit and inflict no harm!”As the Prophet grew into maturity of the body and mind, he became inclined to periodic retreat and withdrawal. His profound inward thoughts, together with the unsuitability of his environment, impelled him to seek solitude.
In his evaluation of phenomena he was never hasty nor dependent on his own ideas and perceptions. He clearly saw a hand that inscribed its will on the pages of nature, and this was itself an indication of the profundity of his vision and the exaltation of his thought.
He would spend the month of Ramadhan alone in the cave of Hira, on the outskirts of Mecca, benefiting fully from the darkness and silence. Far removed from men and their corruption, he engaged in supplication and armed himself with the weapon of faith. He developed his spiritual personality through humble worship in the presence of the Majestic Creator that enveloped his whole being, and through cultivating the thoughts that welled up from the depths of his spirit. In the morning, overflowing with faith and certainty, with spiritual enthusiasm and vigor, he would leave the cave to engage in his daily tasks.
Love of God animated his kind and tranquil face, and he was greatly distressed by the polytheism and foolishness of his people who would prostrate before the idols they had manufactured themselves. He began to struggle against this idolatry, remaining steadfast in the truth through all the trials and hardships he underwent. As his age approached forty, signs of anxiety and distress became marked in his behavior and speech, and he told his loving wife of sounds that were continually re-echoing in his ear and of a dazzling light that would envelop him.
Source: Selected excerpt from Seal of the Prophets and His Message by Sheikh Mujtaba Musawi Lari.
 Ibid., Vol. II, p. 1138.
 Sirat ibn Hisham, Vol. I.