{As he journeyed} (en t(9369) poreuesthai). Luke's common idiom
for a temporal clause (in the journeying), en with the locative
articular middle infinitive. {Drew nigh} (eggizein). Present
active infinitive, was drawing nigh. {Shone round about him}
(auton peri(8873)trapsen). First aorist (ingressive) active
indicative of periastrapt(935c), late compound verb common in LXX
and Byzantine writers, here and  22:6  alone in the N.T. "A light
from heaven suddenly flashed around him." It was like a flash of
lightning. Paul uses the same verb in  22:5 , but in  26:13  he
employs perilampsan (shining around). There are numerous
variations in the historical narrative of Saul's conversion in
 9:3-18  and Luke's report of Paul's two addresses, one on the
steps of the Tower of Antonia facing the murderous mob
( 22:6-16 ), the other before Festus and Agrippa ( 26:12-20 ). A
great deal of capital has been made of these variations to the
discredit of Luke as a writer as if he should have made Paul's
two speeches conform at every point with his own narrative. This
objection has no weight except for those who hold that Luke
composed Paul's speeches freely as some Greek writers used to do.
But, if Luke had notes of Paul's speeches or help from Paul
himself, he naturally preserved the form of the two addresses
without trying to make them agree with each other in all details
or with his own narrative in chapter 9. Luke evidently attached
great importance to the story of Saul's conversion as the turning
point not simply in the career of the man, but an epoch in the
history of apostolic Christianity. In broad outline and in all
essentials the three accounts agree and testify to the
truthfulness of the account of the conversion of Saul. It is
impossible to overestimate the worth to the student of
Christianity of this event from every angle because we have in
Paul's Epistles his own emphasis on the actual appearance of
Jesus to him as the fact that changed his whole life ( 1Co 15:8  Ga 1:16f. ). The variations that appear in the three accounts do
not mar the story, when rightly understood, as we shall see.
Here, for instance, Luke simply mentions "a light from heaven,"
while in  22:6  Paul calls it "a great (hikanon) light" "about
noon" and in  26:13  "above the brightness of the sun," as it
would have to be "at midday" with the sun shining.