Jamieson, Fausset and Brown on Acts 9:3

3. he came near Damascus--so Ac 22:6. Tradition points to a bridge near the city as the spot referred to. Events which are the turning points in one's history so imprint themselves upon the memory that circumstances the most trifling in themselves acquire by connection with them something of their importance, and are recalled with inexpressible interest.

suddenly--At what time of day, it is not said; for artless simplicity reigns here. But he himself emphatically states, in one of his narratives, that it was "about noon" (Ac 22:6), and in the other, "at midday" (Ac 26:13), when there could be no deception.

there shined round about him a light from heaven--"a great light (he himself says) above the brightness of the sun," then shining in its full strength.