It is He who has sent among the unlettered a Messenger of their own, to recite to them His signs, to purify them, and to instruct them in Scripture and Wisdom, although they had been, before, in manifest error. (62:2)
Some of these words are very interesting. God is mentioned in the third person, because the ignorant, primitive, and savage Arabs did not know Him. As there was no "He" in their minds, God first emphasizes the darkness of their nature, their great distance from Him, and indicates that they cannot be addressed directly by Him.
Then God calls them unlettered. They were not all illiterate, but they had no knowledge of God and the Messenger. God, by His infinite Power, sent to this trifling community a Messenger with the greatest will-power, the most sublime nature, the deepest spirituality, and the highest morality, by means of whom He would instruct them in how to become geniuses who would one day govern humanity.
The word among shows that the Messenger was one of them, but only in the sense of being unlettered. Being chosen by God, he could not possibly belong to the Age of Ignorance (pre-Islamic Arabia). However, he had to be unlettered so that God would teach him what he needed to know. God would remove him from his people, educate him, and make him a teacher for all unlettered people.
The phrases to recite to them His signs and to purify them point out that He teaches them about the meanings of the Qur'an and of creation in a gradual manner, and informs them how to become perfect human beings by striving for spiritual perfection. He guides them to higher ranks by explaining the Qur'an and the universe to them, and showing them in minute detail how to lead a balanced and exemplary life in every sphere of activity.
The sentence although they had been, before, in manifest error indicates that God would purify and educate them even though they had gone astray. He did all of this through an unlettered Messenger and by teaching them the Qur'an. Throughout history and even today, this Book has met the needs of countless brilliant scientists, scholars, and saints.
After the Prophet, humanity saw his flag waving everywhere for centuries. Those who follow him, both now and in the past, reach the highest spiritual realms on wings of sainthood, piety, righteousness, knowledge, and science. Those who climbed the steps of good conduct and spirituality, and knowledge and science, both now and in the past, saw in each step the "footprints" of Prophet Muhammad and greet him with "God bless you." They will do the same again in the near future. All so-called original ideas will disappear one by one, like candles blown out, leaving only one "sun"—the Qur'an—that will never set. Its flag will be the only one waving on the horizon, and every generation will rush to it, breaking the chains around their necks.