Excerpts from Books and Wikipedia
"AS FOR THE BÁB—may my soul be His sacrifice!—it was at a young age, that is, in the twenty-fifth year of His blessed life, that He arose to proclaim His Cause. Among the Shí‘ihs it is universally acknowledged that He never studied in any school, nor acquired learning from any teacher. To this the people of Shíráz, each and all, bear witness. Nevertheless, He suddenly appeared before the people, endowed with consummate knowledge, and though but a merchant, confounded all the divines of Persia. Alone, He undertook a task that can scarcely be conceived, for the Persians are known throughout the world for their religious fanaticism. This illustrious Being arose with such power as to shake the foundations of the religious laws, customs, manners, morals, and habits of Persia, and instituted a new law, faith, and religion. Though the eminent men of the State, the majority of the people, and the leaders of religion arose one and all to destroy and annihilate Him, He single-handedly withstood them and set all of Persia in motion. How numerous the divines, the leaders, and the inhabitants of that land who with perfect joy and gladness offered up their lives in His path and hastened to the field of martyrdom!
The government, the nation, the clergy, and prominent leaders sought to extinguish His light, but to no avail. At last His moon rose, His star shone forth, His foundation was secured, and His horizon was flooded with light. He trained a large multitude through divine education and exerted a marvellous influence upon the thoughts, customs, morals, and manners of the Persians. He proclaimed the glad-tidings of the manifestation of the Sun of Bahá to all His followers and readied them for faith and certitude.
The manifestation of such marvellous signs and mighty undertakings, the influence exerted upon the thoughts and minds of the people, the laying of the foundations of progress, and the establishment of the prerequisites of success and prosperity by a young merchant constitute the greatest proof that He was a universal Educator—a fact that no fair-minded person would ever hesitate to acknowledge." [Abdu'l-Baha: Some Answered Questions, p. 30-1]