34 For our Lord appeared to Saul in meekness, since meekness was close to His greatness; that because of His greatness it might be known Who He is Who spoke meekly. For even as His disciples preached on earth of our Lord in meekness and in exaltation—in the meekness of His persecution, and in the exaltation of His signs,— so also our Lord preached of Himself in meekness and in exaltation in Paul's presence— in the exaltation of the potency of the light which flashed, and in the meekness of that meek voice which said; Saul, why do you persecute Me?— so that the preaching of Him which His disciples preached concerning Him in presence of many, should be like to that preaching which He preached concerning Himself. But even as, if He had not spoken meekly, it would not have been made known there that He was meek, so, had He not appeared there as an overpowering light, it would not have been made known there that He was exalted.
Source: On Our Lord (New Advent)