The world has believed this insignificant group of lowly, unimportant, and uneducated men precisely because the divine character of what happened is more marvellously apparent in the insignificance of such witnesses. What gave power to the preachers who persuaded the world was not the eloquence of the words they uttered, but the miracles of the deeds they did.
Those who had not themselves seen Christ rising from the dead and ascending into heaven with His flesh believed the men who said they had seen the miracle, not merely because those men said so, but also because these men themselves worked miracles. For example, many people were astonished to hear these men, who knew but two languages (and, in some cases, only one) suddenly break forth into so many tongues that everybody in the audience understood. They saw a man who had been lame from earliest infancy now, after forty years, stand upright at a word uttered by these witnesses who spoke in the name of Christ. Pieces of cloth that touched their bodies were found to heal the sick. Uncounted people suffering from various diseases set themselves in line in the streets where the Apostles were to pass and where their shadows would fall upon the sick, and many of these people were at once restored to health. Besides many other marvels wrought in the name of Christ, there were even cases of dead men restored to life. (St Augustine, City of God, XXII, 5)